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933 Commits
| Author | SHA1 | Message | Date | |
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Dietmar Eggemann
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d0fe0b9c45 |
sched/fair: Simplify post_init_entity_util_avg() by calling it with a task_struct pointer argument
Since commit:
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Vincent Guittot
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039ae8bcf7 |
sched/fair: Fix O(nr_cgroups) in the load balancing path
This re-applies the commit reverted here: commit |
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Vincent Guittot
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31bc6aeaab |
sched/fair: Optimize update_blocked_averages()
Removing a cfs_rq from rq->leaf_cfs_rq_list can break the parent/child
ordering of the list when it will be added back. In order to remove an
empty and fully decayed cfs_rq, we must remove its children too, so they
will be added back in the right order next time.
With a normal decay of PELT, a parent will be empty and fully decayed
if all children are empty and fully decayed too. In such a case, we just
have to ensure that the whole branch will be added when a new task is
enqueued. This is default behavior since :
commit
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Ingo Molnar
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c9ba7560c5 |
Linux 5.0-rc6
-----BEGIN PGP SIGNATURE----- iQFRBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAlxgqNUeHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGwsoH+OVXu0NQofwTvVru 8lgF3BSDG2mhf7mxbBBlBizGVy9jnjRNGCFMC+Jq8IwiFLwprja/G27kaDTkpuF1 PHC3yfjKvjTeUP5aNdHlmxv6j1sSJfZl0y46DQal4UeTG/Giq8TFTi+Tbz7Wb/WV yCx4Lr8okAwTuNhnL8ojUCVIpd3c8QsyR9v6nEQ14Mj+MvEbokyTkMJV0bzOrM38 JOB+/X1XY4JPZ6o3MoXrBca3bxbAJzMneq+9CWw1U5eiIG3msg4a+Ua3++RQMDNr 8BP0yCZ6wo32S8uu0PI6HrZaBnLYi5g9Wh7Q7yc0mn1Uh1zWFykA6TtqK90agJeR A6Ktjw== =scY4 -----END PGP SIGNATURE----- Merge tag 'v5.0-rc6' into sched/core, to pick up fixes Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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f678331973 |
sched/fair: Fix insertion in rq->leaf_cfs_rq_list
Sargun reported a crash: "I picked up |
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Peter Zijlstra
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5d299eabea |
sched/fair: Add tmp_alone_branch assertion
The magic in list_add_leaf_cfs_rq() requires that at the end of enqueue_task_fair(): rq->tmp_alone_branch == &rq->lead_cfs_rq_list If this is violated, list integrity is compromised for list entries and the tmp_alone_branch pointer might dangle. Also, reflow list_add_leaf_cfs_rq() while there. This looses one indentation level and generates a form that's convenient for the next patch. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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10a35e6812 |
sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity
util_est is mainly meant to be a lower-bound for tasks utilization. That's why task_util_est() returns the actual util_avg when it's higher than the estimated utilization. With new invaraince signal and without any special check on samples collection, if a task is limited because of thermal capping for example, we could end up overestimating its utilization and thus perhaps generating an unwanted frequency spike when the capping is relaxed... and (even worst) it will take some more activations for the estimated utilization to converge back to the actual utilization. Since we cannot easily know if there is idle time in a CPU when a task completes an activation with a utilization higher then the CPU capacity, we skip the sampling when utilization is higher than CPU's capacity. Suggested-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: pjt@google.com Cc: pkondeti@codeaurora.org Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Link: https://lkml.kernel.org/r/1548257214-13745-4-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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2312729688 |
sched/fair: Update scale invariance of PELT
The current implementation of load tracking invariance scales the
contribution with current frequency and uarch performance (only for
utilization) of the CPU. One main result of this formula is that the
figures are capped by current capacity of CPU. Another one is that the
load_avg is not invariant because not scaled with uarch.
The util_avg of a periodic task that runs r time slots every p time slots
varies in the range :
U * (1-y^r)/(1-y^p) * y^i < Utilization < U * (1-y^r)/(1-y^p)
with U is the max util_avg value = SCHED_CAPACITY_SCALE
At a lower capacity, the range becomes:
U * C * (1-y^r')/(1-y^p) * y^i' < Utilization < U * C * (1-y^r')/(1-y^p)
with C reflecting the compute capacity ratio between current capacity and
max capacity.
so C tries to compensate changes in (1-y^r') but it can't be accurate.
Instead of scaling the contribution value of PELT algo, we should scale the
running time. The PELT signal aims to track the amount of computation of
tasks and/or rq so it seems more correct to scale the running time to
reflect the effective amount of computation done since the last update.
In order to be fully invariant, we need to apply the same amount of
running time and idle time whatever the current capacity. Because running
at lower capacity implies that the task will run longer, we have to ensure
that the same amount of idle time will be applied when system becomes idle
and no idle time has been "stolen". But reaching the maximum utilization
value (SCHED_CAPACITY_SCALE) means that the task is seen as an
always-running task whatever the capacity of the CPU (even at max compute
capacity). In this case, we can discard this "stolen" idle times which
becomes meaningless.
In order to achieve this time scaling, a new clock_pelt is created per rq.
The increase of this clock scales with current capacity when something
is running on rq and synchronizes with clock_task when rq is idle. With
this mechanism, we ensure the same running and idle time whatever the
current capacity. This also enables to simplify the pelt algorithm by
removing all references of uarch and frequency and applying the same
contribution to utilization and loads. Furthermore, the scaling is done
only once per update of clock (update_rq_clock_task()) instead of during
each update of sched_entities and cfs/rt/dl_rq of the rq like the current
implementation. This is interesting when cgroup are involved as shown in
the results below:
On a hikey (octo Arm64 platform).
Performance cpufreq governor and only shallowest c-state to remove variance
generated by those power features so we only track the impact of pelt algo.
each test runs 16 times:
./perf bench sched pipe
(higher is better)
kernel tip/sched/core + patch
ops/seconds ops/seconds diff
cgroup
root 59652(+/- 0.18%) 59876(+/- 0.24%) +0.38%
level1 55608(+/- 0.27%) 55923(+/- 0.24%) +0.57%
level2 52115(+/- 0.29%) 52564(+/- 0.22%) +0.86%
hackbench -l 1000
(lower is better)
kernel tip/sched/core + patch
duration(sec) duration(sec) diff
cgroup
root 4.453(+/- 2.37%) 4.383(+/- 2.88%) -1.57%
level1 4.859(+/- 8.50%) 4.830(+/- 7.07%) -0.60%
level2 5.063(+/- 9.83%) 4.928(+/- 9.66%) -2.66%
Then, the responsiveness of PELT is improved when CPU is not running at max
capacity with this new algorithm. I have put below some examples of
duration to reach some typical load values according to the capacity of the
CPU with current implementation and with this patch. These values has been
computed based on the geometric series and the half period value:
Util (%) max capacity half capacity(mainline) half capacity(w/ patch)
972 (95%) 138ms not reachable 276ms
486 (47.5%) 30ms 138ms 60ms
256 (25%) 13ms 32ms 26ms
On my hikey (octo Arm64 platform) with schedutil governor, the time to
reach max OPP when starting from a null utilization, decreases from 223ms
with current scale invariance down to 121ms with the new algorithm.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: patrick.bellasi@arm.com
Cc: pjt@google.com
Cc: pkondeti@codeaurora.org
Cc: quentin.perret@arm.com
Cc: rjw@rjwysocki.net
Cc: srinivas.pandruvada@linux.intel.com
Cc: thara.gopinath@linaro.org
Link: https://lkml.kernel.org/r/1548257214-13745-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Vincent Guittot
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62478d9911 |
sched/fair: Move the rq_of() helper function
Move rq_of() helper function so it can be used in pelt.c [ mingo: Improve readability while at it. ] Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: patrick.bellasi@arm.com Cc: pjt@google.com Cc: pkondeti@codeaurora.org Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Link: https://lkml.kernel.org/r/1548257214-13745-2-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Elena Reshetova
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c45a779524 |
sched/fair: Convert numa_group.refcount to refcount_t
atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable numa_group.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. ** Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the numa_group.refcount it might make a difference in following places: - get_numa_group(): increment in refcount_inc_not_zero() only guarantees control dependency on success vs. fully ordered atomic counterpart - put_numa_group(): decrement in refcount_dec_and_test() only provides RELEASE ordering and control dependency on success vs. fully ordered atomic counterpart Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1547814450-18902-4-git-send-email-elena.reshetova@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Josh Poimboeuf
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b284909aba |
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
With the following commit: |
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Vincent Guittot
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46a745d905 |
sched/fair: Fix unnecessary increase of balance interval
In case of active balancing, we increase the balance interval to cover pinned tasks cases not covered by all_pinned logic. Neverthless, the active migration triggered by asym packing should be treated as the normal unbalanced case and reset the interval to default value, otherwise active migration for asym_packing can be easily delayed for hundreds of ms because of this pinned task detection mechanism. The same happens to other conditions tested in need_active_balance() like misfit task and when the capacity of src_cpu is reduced compared to dst_cpu (see comments in need_active_balance() for details). Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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4ad4e481bd |
sched/fair: Fix rounding bug for asym packing
When check_asym_packing() is triggered, the imbalance is set to: busiest_stat.avg_load * busiest_stat.group_capacity / SCHED_CAPACITY_SCALE But busiest_stat.avg_load equals: sgs->group_load * SCHED_CAPACITY_SCALE / sgs->group_capacity These divisions can generate a rounding that will make imbalance slightly lower than the weighted load of the cfs_rq. But this is enough to skip the rq in find_busiest_queue() and prevents asym migration from happening. Directly set imbalance to busiest's sgs->group_load to remove the rounding. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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a062d16449 |
sched/fair: Trigger asym_packing during idle load balance
Newly idle load balancing is not always triggered when a CPU becomes idle. This prevents the scheduler from getting a chance to migrate the task for asym packing. Enable active migration during idle load balance too. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
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c0ad4aa4d8 |
sched/fair: Robustify CFS-bandwidth timer locking
Traditionally hrtimer callbacks were run with IRQs disabled, but with the introduction of HRTIMER_MODE_SOFT it is possible they run from SoftIRQ context, which does _NOT_ have IRQs disabled. Allow for the CFS bandwidth timers (period_timer and slack_timer) to be ran from SoftIRQ context; this entails removing the assumption that IRQs are already disabled from the locking. While mainline doesn't strictly need this, -RT forces all timers not explicitly marked with MODE_HARD into MODE_SOFT and trips over this. And marking these timers as MODE_HARD doesn't make sense as they're not required for RT operation and can potentially be quite expensive. Reported-by: Tom Putzeys <tom.putzeys@be.atlascopco.com> Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190107125231.GE14122@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
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f8a696f25b |
sched/core: Give DCE a fighting chance
All that fancy new Energy-Aware scheduling foo is hidden behind a static_key, which is awesome if you have the stuff enabled in your config. However, when you lack all the prerequisites it doesn't make any sense to pretend we'll ever actually run this, so provide a little more clue to the compiler so it can more agressively delete the code. text data bss dec hex filename 50297 976 96 51369 c8a9 defconfig-build/kernel/sched/fair.o 49227 944 96 50267 c45b defconfig-build/kernel/sched/fair.o Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Masahiro Yamada
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e9666d10a5 |
jump_label: move 'asm goto' support test to Kconfig
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label". The jump label is controlled by HAVE_JUMP_LABEL, which is defined like this: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif We can improve this by testing 'asm goto' support in Kconfig, then make JUMP_LABEL depend on CC_HAS_ASM_GOTO. Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will match to the real kernel capability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Sedat Dilek <sedat.dilek@gmail.com> |
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Linus Torvalds
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c40f7d74c7 |
sched/fair: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b
Zhipeng Xie, Xie XiuQi and Sargun Dhillon reported lockups in the scheduler under high loads, starting at around the v4.18 time frame, and Zhipeng Xie tracked it down to bugs in the rq->leaf_cfs_rq_list manipulation. Do a (manual) revert of: |
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Olof Johansson
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6d101ba6be |
sched/fair: Fix warning on non-SMP build
Caused by making the variable static:
kernel/sched/fair.c:119:21: warning: 'capacity_margin' defined but not used [-Wunused-variable]
Seems easiest to just move it up under the existing ifdef CONFIG_SMP
that's a few lines above.
Fixes:
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Linus Torvalds
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17bf423a1f |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Introduce "Energy Aware Scheduling" - by Quentin Perret.
This is a coherent topology description of CPUs in cooperation with
the PM subsystem, with the goal to schedule more energy-efficiently
on asymetric SMP platform - such as waking up tasks to the more
energy-efficient CPUs first, as long as the system isn't
oversubscribed.
For details of the design, see:
https://lore.kernel.org/lkml/20180724122521.22109-1-quentin.perret@arm.com/
- Misc cleanups and smaller enhancements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
sched/fair: Select an energy-efficient CPU on task wake-up
sched/fair: Introduce an energy estimation helper function
sched/fair: Add over-utilization/tipping point indicator
sched/fair: Clean-up update_sg_lb_stats parameters
sched/toplogy: Introduce the 'sched_energy_present' static key
sched/topology: Make Energy Aware Scheduling depend on schedutil
sched/topology: Disable EAS on inappropriate platforms
sched/topology: Add lowest CPU asymmetry sched_domain level pointer
sched/topology: Reference the Energy Model of CPUs when available
PM: Introduce an Energy Model management framework
sched/cpufreq: Prepare schedutil for Energy Aware Scheduling
sched/topology: Relocate arch_scale_cpu_capacity() to the internal header
sched/core: Remove unnecessary unlikely() in push_*_task()
sched/topology: Remove the ::smt_gain field from 'struct sched_domain'
sched: Fix various typos in comments
sched/core: Clean up the #ifdef block in add_nr_running()
sched/fair: Make some variables static
sched/core: Create task_has_idle_policy() helper
sched/fair: Add lsub_positive() and use it consistently
sched/fair: Mask UTIL_AVG_UNCHANGED usages
...
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Quentin Perret
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732cd75b8c |
sched/fair: Select an energy-efficient CPU on task wake-up
If an Energy Model (EM) is available and if the system isn't overutilized, re-route waking tasks into an energy-aware placement algorithm. The selection of an energy-efficient CPU for a task is achieved by estimating the impact on system-level active energy resulting from the placement of the task on the CPU with the highest spare capacity in each performance domain. This strategy spreads tasks in a performance domain and avoids overly aggressive task packing. The best CPU energy-wise is then selected if it saves a large enough amount of energy with respect to prev_cpu. Although it has already shown significant benefits on some existing targets, this approach cannot scale to platforms with numerous CPUs. This is an attempt to do something useful as writing a fast heuristic that performs reasonably well on a broad spectrum of architectures isn't an easy task. As such, the scope of usability of the energy-aware wake-up path is restricted to systems with the SD_ASYM_CPUCAPACITY flag set, and where the EM isn't too complex. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-15-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Quentin Perret
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390031e4c3 |
sched/fair: Introduce an energy estimation helper function
In preparation for the definition of an energy-aware wakeup path, introduce a helper function to estimate the consequence on system energy when a specific task wakes-up on a specific CPU. compute_energy() estimates the capacity state to be reached by all performance domains and estimates the consumption of each online CPU according to its Energy Model and its percentage of busy time. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-14-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Morten Rasmussen
|
2802bf3cd9 |
sched/fair: Add over-utilization/tipping point indicator
Energy-aware scheduling is only meant to be active while the system is
_not_ over-utilized. That is, there are spare cycles available to shift
tasks around based on their actual utilization to get a more
energy-efficient task distribution without depriving any tasks. When
above the tipping point task placement is done the traditional way based
on load_avg, spreading the tasks across as many cpus as possible based
on priority scaled load to preserve smp_nice. Below the tipping point we
want to use util_avg instead. We need to define a criteria for when we
make the switch.
The util_avg for each cpu converges towards 100% regardless of how many
additional tasks we may put on it. If we define over-utilized as:
sum_{cpus}(rq.cfs.avg.util_avg) + margin > sum_{cpus}(rq.capacity)
some individual cpus may be over-utilized running multiple tasks even
when the above condition is false. That should be okay as long as we try
to spread the tasks out to avoid per-cpu over-utilization as much as
possible and if all tasks have the _same_ priority. If the latter isn't
true, we have to consider priority to preserve smp_nice.
For example, we could have n_cpus nice=-10 util_avg=55% tasks and
n_cpus/2 nice=0 util_avg=60% tasks. Balancing based on util_avg we are
likely to end up with nice=-10 tasks sharing cpus and nice=0 tasks
getting their own as we 1.5*n_cpus tasks in total and 55%+55% is less
over-utilized than 55%+60% for those cpus that have to be shared. The
system utilization is only 85% of the system capacity, but we are
breaking smp_nice.
To be sure not to break smp_nice, we have defined over-utilization
conservatively as when any cpu in the system is fully utilized at its
highest frequency instead:
cpu_rq(any).cfs.avg.util_avg + margin > cpu_rq(any).capacity
IOW, as soon as one cpu is (nearly) 100% utilized, we switch to load_avg
to factor in priority to preserve smp_nice.
With this definition, we can skip periodic load-balance as no cpu has an
always-running task when the system is not over-utilized. All tasks will
be periodic and we can balance them at wake-up. This conservative
condition does however mean that some scenarios that could benefit from
energy-aware decisions even if one cpu is fully utilized would not get
those benefits.
For systems where some cpus might have reduced capacity on some cpus
(RT-pressure and/or big.LITTLE), we want periodic load-balance checks as
soon a just a single cpu is fully utilized as it might one of those with
reduced capacity and in that case we want to migrate it.
[ peterz: Added a comment explaining why new tasks are not accounted during
overutilization detection. ]
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adharmap@codeaurora.org
Cc: chris.redpath@arm.com
Cc: currojerez@riseup.net
Cc: dietmar.eggemann@arm.com
Cc: edubezval@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: javi.merino@kernel.org
Cc: joel@joelfernandes.org
Cc: juri.lelli@redhat.com
Cc: patrick.bellasi@arm.com
Cc: pkondeti@codeaurora.org
Cc: rjw@rjwysocki.net
Cc: skannan@codeaurora.org
Cc: smuckle@google.com
Cc: srinivas.pandruvada@linux.intel.com
Cc: thara.gopinath@linaro.org
Cc: tkjos@google.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Cc: viresh.kumar@linaro.org
Link: https://lkml.kernel.org/r/20181203095628.11858-13-quentin.perret@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Quentin Perret
|
630246a06a |
sched/fair: Clean-up update_sg_lb_stats parameters
In preparation for the introduction of a new root domain flag which can be set during load balance (the 'overutilized' flag), clean-up the set of parameters passed to update_sg_lb_stats(). More specifically, the 'local_group' and 'local_idx' parameters can be removed since they can easily be reconstructed from within the function. While at it, transform the 'overload' parameter into a flag stored in the 'sg_status' parameter hence facilitating the definition of new flags when needed. Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-12-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Quentin Perret
|
011b27bb5d |
sched/topology: Add lowest CPU asymmetry sched_domain level pointer
Add another member to the family of per-cpu sched_domain shortcut pointers. This one, sd_asym_cpucapacity, points to the lowest level at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the sd_asym shortcut to sd_asym_packing to avoid confusions. Generally speaking, the largest opportunity to save energy via scheduling comes from a smarter exploitation of heterogeneous platforms (i.e. big.LITTLE). Consequently, the sd_asym_cpucapacity shortcut will be used at first as the lowest domain where Energy-Aware Scheduling (EAS) should be applied. For example, it is possible to apply EAS within a socket on a multi-socket system, as long as each socket has an asymmetric topology. Energy-aware cross-sockets wake-up balancing will only happen when the system is over-utilized, or this_cpu and prev_cpu are in different sockets. Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-7-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Andrea Parri
|
80eb865768 |
sched/fair: Clean up comment in nohz_idle_balance()
Concerning the comment associated to the atomic_fetch_andnot() in nohz_idle_balance(), Vincent explains [1]: "[...] the comment is useless and can be removed [...] it was referring to a line code above the comment that was present in a previous iteration of the patchset. This line disappeared in final version but the comment has stayed." So remove the comment. Vincent also points out that the full ordering associated to the atomic_fetch_andnot() primitive could be relaxed, but this patch insists on the current more conservative/fully ordered solution: "Performance" isn't a concern, stay away from "correctness"/subtle relaxed (re)ordering if possible..., just make sure not to confuse the next reader with misleading/out-of-date comments. [1] http://lkml.kernel.org/r/CAKfTPtBjA-oCBRkO6__npQwL3+HLjzk7riCcPU1R7YdO-EpuZg@mail.gmail.com Suggested-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20181127110110.5533-1-andrea.parri@amarulasolutions.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Ingo Molnar
|
dfcb245e28 |
sched: Fix various typos in comments
Go over the scheduler source code and fix common typos in comments - and a typo in an actual variable name. No change in functionality intended. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Muchun Song
|
ed8885a144 |
sched/fair: Make some variables static
The variables are local to the source and do not need to be in global scope, so make them static. Signed-off-by: Muchun Song <smuchun@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181110075202.61172-1-smuchun@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Viresh Kumar
|
1da1843f9f |
sched/core: Create task_has_idle_policy() helper
We already have task_has_rt_policy() and task_has_dl_policy() helpers, create task_has_idle_policy() as well and update sched core to start using it. While at it, use task_has_dl_policy() at one more place. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/ce3915d5b490fc81af926a3b6bfb775e7188e005.1541416894.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
|
b5c0ce7bd1 |
sched/fair: Add lsub_positive() and use it consistently
The following pattern:
var -= min_t(typeof(var), var, val);
is used multiple times in fair.c.
The existing sub_positive() already captures that pattern, but it also
adds an explicit load-store to properly support lockless observations.
In other cases the pattern above is used to update local, and/or not
concurrently accessed, variables.
Let's add a simpler version of sub_positive(), targeted at local variables
updates, which gives the same readability benefits at calling sites,
without enforcing {READ,WRITE}_ONCE() barriers.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Steve Muckle <smuckle@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/lkml/20181031184527.GA3178@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Patrick Bellasi
|
92a801e5d5 |
sched/fair: Mask UTIL_AVG_UNCHANGED usages
The _task_util_est() is mainly used to add/remove the task contribution to/from the rq's estimated utilization at task enqueue/dequeue time. In both cases we ensure the UTIL_AVG_UNCHANGED flag is set to keep consistency between enqueue and dequeue time while still being transparent to update_load_avg calls which will eventually reset the flag. Let's move the flag forcing within _task_util_est() itself so that we can simplify calling code by hiding that estimated utilization implementation detail into one of its internal functions. This will affect also the "public" API task_util_est() but we know that the flag will (eventually) impact just on the LSB of the estimated utilization, thus it's certainly acceptable. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/20181105145400.935-3-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Ingo Molnar
|
59e1678c29 |
Merge branch 'sched/urgent' into sched/core, to pick up dependent fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Patrick Bellasi
|
c469933e77 |
sched/fair: Fix cpu_util_wake() for 'execl' type workloads
A ~10% regression has been reported for UnixBench's execl throughput test by Aaron Lu and Ye Xiaolong: https://lkml.org/lkml/2018/10/30/765 That test is pretty simple, it does a "recursive" execve() syscall on the same binary. Starting from the syscall, this sequence is possible: do_execve() do_execveat_common() __do_execve_file() sched_exec() select_task_rq_fair() <==| Task already enqueued find_idlest_cpu() find_idlest_group() capacity_spare_wake() <==| Functions not called from cpu_util_wake() | the wakeup path which means we can end up calling cpu_util_wake() not only from the "wakeup path", as its name would suggest. Indeed, the task doing an execve() syscall is already enqueued on the CPU we want to get the cpu_util_wake() for. The estimated utilization for a CPU computed in cpu_util_wake() was written under the assumption that function can be called only from the wakeup path. If instead the task is already enqueued, we end up with a utilization which does not remove the current task's contribution from the estimated utilization of the CPU. This will wrongly assume a reduced spare capacity on the current CPU and increase the chances to migrate the task on execve. The regression is tracked down to: commit |
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Yi Wang
|
e1ff516a56 |
sched/fair: Fix a comment in task_numa_fault()
Duplicated 'case it'. Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Reviewed-by: Xi Xu <xu.xi8@zte.com.cn> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1541379013-11352-1-git-send-email-wang.yi59@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Valentin Schneider
|
3f130a37c4 |
sched/fair: Don't increase sd->balance_interval on newidle balance
When load_balance() fails to move some load because of task affinity,
we end up increasing sd->balance_interval to delay the next periodic
balance in the hopes that next time we look, that annoying pinned
task(s) will be gone.
However, idle_balance() pays no attention to sd->balance_interval, yet
it will still lead to an increase in balance_interval in case of
pinned tasks.
If we're going through several newidle balances (e.g. we have a
periodic task), this can lead to a huge increase of the
balance_interval in a very small amount of time.
To prevent that, don't increase the balance interval when going
through a newidle balance.
This is a similar approach to what is done in commit
|
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Valentin Schneider
|
47b7aee14f |
sched/fair: Clean up load_balance() condition
The alignment of the condition is off, clean that up. Also, logical operators have lower precedence than bitwise/relational operators, so remove one layer of parentheses to make the condition a bit simpler to follow. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar.Eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: patrick.bellasi@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1537974727-30788-1-git-send-email-valentin.schneider@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
|
42f52e1c59 |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"The main changes are:
- Migrate CPU-intense 'misfit' tasks on asymmetric capacity systems,
to better utilize (much) faster 'big core' CPUs. (Morten Rasmussen,
Valentin Schneider)
- Topology handling improvements, in particular when CPU capacity
changes and related load-balancing fixes/improvements (Morten
Rasmussen)
- ... plus misc other improvements, fixes and updates"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
sched/completions/Documentation: Add recommendation for dynamic and ONSTACK completions
sched/completions/Documentation: Clean up the document some more
sched/completions/Documentation: Fix a couple of punctuation nits
cpu/SMT: State SMT is disabled even with nosmt and without "=force"
sched/core: Fix comment regarding nr_iowait_cpu() and get_iowait_load()
sched/fair: Remove setting task's se->runnable_weight during PELT update
sched/fair: Disable LB_BIAS by default
sched/pelt: Fix warning and clean up IRQ PELT config
sched/topology: Make local variables static
sched/debug: Use symbolic names for task state constants
sched/numa: Remove unused numa_stats::nr_running field
sched/numa: Remove unused code from update_numa_stats()
sched/debug: Explicitly cast sched_feat() to bool
sched/core: Disable SD_PREFER_SIBLING on asymmetric CPU capacity domains
sched/fair: Don't move tasks to lower capacity CPUs unless necessary
sched/fair: Set rq->rd->overload when misfit
sched/fair: Wrap rq->rd->overload accesses with READ/WRITE_ONCE()
sched/core: Change root_domain->overload type to int
sched/fair: Change 'prefer_sibling' type to bool
sched/fair: Kick nohz balance if rq->misfit_task_load
...
|
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Song Muchun
|
9845c49cc9 |
sched/fair: Fix the min_vruntime update logic in dequeue_entity()
The comment and the code around the update_min_vruntime() call in dequeue_entity() are not in agreement. From commit: |
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Phil Auld
|
baa9be4ffb |
sched/fair: Fix throttle_list starvation with low CFS quota
With a very low cpu.cfs_quota_us setting, such as the minimum of 1000, distribute_cfs_runtime may not empty the throttled_list before it runs out of runtime to distribute. In that case, due to the change from |
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Mel Gorman
|
37355bdc5a |
sched/numa: Migrate pages to local nodes quicker early in the lifetime of a task
Automatic NUMA Balancing uses a multi-stage pass to decide whether a page
should migrate to a local node. This filter avoids excessive ping-ponging
if a page is shared or used by threads that migrate cross-node frequently.
Threads inherit both page tables and the preferred node ID from the
parent. This means that threads can trigger hinting faults earlier than
a new task which delays scanning for a number of seconds. As it can be
load balanced very early in its lifetime there can be an unnecessary delay
before it starts migrating thread-local data. This patch migrates private
pages faster early in the lifetime of a thread using the sequence counter
as an identifier of new tasks.
With this patch applied, STREAM performance is the same as 4.17 even though
processes are not spread cross-node prematurely. Other workloads showed
a mix of minor gains and losses. This is somewhat expected most workloads
are not very sensitive to the starting conditions of a process.
4.19.0-rc5 4.19.0-rc5 4.17.0
numab-v1r1 fastmigrate-v1r1 vanilla
MB/sec copy 43298.52 ( 0.00%) 47335.46 ( 9.32%) 47219.24 ( 9.06%)
MB/sec scale 30115.06 ( 0.00%) 32568.12 ( 8.15%) 32527.56 ( 8.01%)
MB/sec add 32825.12 ( 0.00%) 36078.94 ( 9.91%) 35928.02 ( 9.45%)
MB/sec triad 32549.52 ( 0.00%) 35935.94 ( 10.40%) 35969.88 ( 10.51%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001100525.29789-3-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Vincent Guittot
|
11d4afd4ff |
sched/pelt: Fix warning and clean up IRQ PELT config
Create a config for enabling irq load tracking in the scheduler. irq load tracking is useful only when irq or paravirtual time is accounted but it's only possible with SMP for now. Also use __maybe_unused to remove the compilation warning in update_rq_clock_task() that has been introduced by: |
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Ingo Molnar
|
b429f71bca |
Merge branch 'sched/urgent' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
|
6fd98e775f |
sched/numa: Avoid task migration for small NUMA improvement
If NUMA improvement from the task migration is going to be very minimal, then avoid task migration. Specjbb2005 results (8 warehouses) Higher bops are better 2 Socket - 2 Node Haswell - X86 JVMS Prev Current %Change 4 198512 205910 3.72673 1 313559 318491 1.57291 2 Socket - 4 Node Power8 - PowerNV JVMS Prev Current %Change 8 74761.9 74935.9 0.232739 1 214874 226796 5.54837 2 Socket - 2 Node Power9 - PowerNV JVMS Prev Current %Change 4 180536 189780 5.12031 1 210281 205695 -2.18089 4 Socket - 4 Node Power7 - PowerVM JVMS Prev Current %Change 8 56511.4 60370 6.828 1 104899 108100 3.05151 1/7 cases is regressing, if we look at events migrate_pages seem to vary the most especially in the regressing case. Also some amount of variance is expected between different runs of Specjbb2005. Some events stats before and after applying the patch. perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 13,818,546 13,801,554 migrations 1,149,960 1,151,541 faults 385,583 433,246 cache-misses 55,259,546,768 55,168,691,835 sched:sched_move_numa 2,257 2,551 sched:sched_stick_numa 9 24 sched:sched_swap_numa 512 904 migrate:mm_migrate_pages 2,225 1,571 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 72692 113682 numa_hint_faults_local 62270 102163 numa_hit 238762 240181 numa_huge_pte_updates 48 36 numa_interleave 75 64 numa_local 238676 240103 numa_other 86 78 numa_pages_migrated 2225 1564 numa_pte_updates 98557 134080 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 3,173,490 3,079,150 migrations 36,966 31,455 faults 108,776 99,081 cache-misses 12,200,075,320 11,588,126,740 sched:sched_move_numa 1,264 1 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 0 migrate:mm_migrate_pages 899 36 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 21109 430 numa_hint_faults_local 17120 77 numa_hit 72934 71277 numa_huge_pte_updates 42 0 numa_interleave 33 22 numa_local 72866 71218 numa_other 68 59 numa_pages_migrated 915 23 numa_pte_updates 42326 0 perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 8,312,022 8,707,565 migrations 231,705 171,342 faults 310,242 310,820 cache-misses 402,324,573 136,115,400 sched:sched_move_numa 193 215 sched:sched_stick_numa 0 6 sched:sched_swap_numa 3 24 migrate:mm_migrate_pages 93 162 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 11838 8985 numa_hint_faults_local 11216 8154 numa_hit 90689 93819 numa_huge_pte_updates 0 0 numa_interleave 1579 882 numa_local 89634 93496 numa_other 1055 323 numa_pages_migrated 92 169 numa_pte_updates 12109 9217 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 2,170,481 2,152,072 migrations 10,126 10,704 faults 160,962 164,376 cache-misses 10,834,845 3,818,437 sched:sched_move_numa 10 16 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 7 migrate:mm_migrate_pages 2 199 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 403 2248 numa_hint_faults_local 358 1666 numa_hit 25898 25704 numa_huge_pte_updates 0 0 numa_interleave 207 200 numa_local 25860 25679 numa_other 38 25 numa_pages_migrated 2 197 numa_pte_updates 400 2234 perf stats 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 110,339,633 93,330,595 migrations 4,139,812 4,122,061 faults 863,622 865,979 cache-misses 231,838,045,660 225,395,083,479 sched:sched_move_numa 2,196 2,372 sched:sched_stick_numa 33 24 sched:sched_swap_numa 544 769 migrate:mm_migrate_pages 2,469 1,677 vmstat 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 85748 91638 numa_hint_faults_local 66831 78096 numa_hit 242213 242225 numa_huge_pte_updates 0 0 numa_interleave 0 2 numa_local 242211 242219 numa_other 2 6 numa_pages_migrated 2376 1515 numa_pte_updates 86233 92274 perf stats 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 59,331,057 51,487,271 migrations 552,019 537,170 faults 266,586 256,921 cache-misses 73,796,312,990 70,073,831,187 sched:sched_move_numa 981 576 sched:sched_stick_numa 54 24 sched:sched_swap_numa 286 327 migrate:mm_migrate_pages 713 726 vmstat 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 14807 12000 numa_hint_faults_local 5738 5024 numa_hit 36230 36470 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 36228 36465 numa_other 2 5 numa_pages_migrated 703 726 numa_pte_updates 14742 11930 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1537552141-27815-7-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Mel Gorman
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05cbdf4f5c |
sched/numa: Limit the conditions where scan period is reset
migrate_task_rq_fair() resets the scan rate for NUMA balancing on every cross-node migration. In the event of excessive load balancing due to saturation, this may result in the scan rate being pegged at maximum and further overloading the machine. This patch only resets the scan if NUMA balancing is active, a preferred node has been selected and the task is being migrated from the preferred node as these are the most harmful. For example, a migration to the preferred node does not justify a faster scan rate. Similarly, a migration between two nodes that are not preferred is probably bouncing due to over-saturation of the machine. In that case, scanning faster and trapping more NUMA faults will further overload the machine. Specjbb2005 results (8 warehouses) Higher bops are better 2 Socket - 2 Node Haswell - X86 JVMS Prev Current %Change 4 203370 205332 0.964744 1 328431 319785 -2.63252 2 Socket - 4 Node Power8 - PowerNV JVMS Prev Current %Change 1 206070 206585 0.249915 2 Socket - 2 Node Power9 - PowerNV JVMS Prev Current %Change 4 188386 189162 0.41192 1 201566 213760 6.04963 4 Socket - 4 Node Power7 - PowerVM JVMS Prev Current %Change 8 59157.4 58736.8 -0.710985 1 105495 105419 -0.0720413 Some events stats before and after applying the patch. perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 13,825,492 14,285,708 migrations 1,152,509 1,180,621 faults 371,948 339,114 cache-misses 55,654,206,041 55,205,631,894 sched:sched_move_numa 1,856 843 sched:sched_stick_numa 4 6 sched:sched_swap_numa 428 219 migrate:mm_migrate_pages 898 365 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 57146 26907 numa_hint_faults_local 51612 24279 numa_hit 238164 239771 numa_huge_pte_updates 16 0 numa_interleave 63 68 numa_local 238085 239688 numa_other 79 83 numa_pages_migrated 883 363 numa_pte_updates 67540 27415 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 3,288,525 3,202,779 migrations 38,652 37,186 faults 111,678 106,076 cache-misses 12,111,197,376 12,024,873,744 sched:sched_move_numa 900 931 sched:sched_stick_numa 0 0 sched:sched_swap_numa 5 1 migrate:mm_migrate_pages 714 637 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 18572 17409 numa_hint_faults_local 14850 14367 numa_hit 73197 73953 numa_huge_pte_updates 11 20 numa_interleave 25 25 numa_local 73138 73892 numa_other 59 61 numa_pages_migrated 712 668 numa_pte_updates 24021 27276 perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 8,451,543 8,474,013 migrations 202,804 254,934 faults 310,024 320,506 cache-misses 253,522,507 110,580,458 sched:sched_move_numa 213 725 sched:sched_stick_numa 0 0 sched:sched_swap_numa 2 7 migrate:mm_migrate_pages 88 145 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 11830 22797 numa_hint_faults_local 11301 21539 numa_hit 90038 89308 numa_huge_pte_updates 0 0 numa_interleave 855 865 numa_local 89796 88955 numa_other 242 353 numa_pages_migrated 88 149 numa_pte_updates 12039 22930 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 2,049,153 2,195,628 migrations 11,405 11,179 faults 162,309 149,656 cache-misses 7,203,343 8,117,515 sched:sched_move_numa 22 49 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 0 migrate:mm_migrate_pages 1 5 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 1693 3577 numa_hint_faults_local 1669 3476 numa_hit 25177 26142 numa_huge_pte_updates 0 0 numa_interleave 194 358 numa_local 24993 26042 numa_other 184 100 numa_pages_migrated 1 5 numa_pte_updates 1577 3587 perf stats 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 94,515,937 100,602,296 migrations 4,203,554 4,135,630 faults 832,697 789,256 cache-misses 226,248,698,331 226,160,621,058 sched:sched_move_numa 1,730 1,366 sched:sched_stick_numa 14 16 sched:sched_swap_numa 432 374 migrate:mm_migrate_pages 1,398 1,350 vmstat 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 80079 47857 numa_hint_faults_local 68620 39768 numa_hit 241187 240165 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 241186 240165 numa_other 1 0 numa_pages_migrated 1347 1224 numa_pte_updates 80729 48354 perf stats 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 63,704,961 58,515,496 migrations 573,404 564,845 faults 230,878 245,807 cache-misses 76,568,222,781 73,603,757,976 sched:sched_move_numa 509 996 sched:sched_stick_numa 31 10 sched:sched_swap_numa 182 193 migrate:mm_migrate_pages 541 646 vmstat 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 8501 13422 numa_hint_faults_local 2960 5619 numa_hit 35526 36118 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 35526 36116 numa_other 0 2 numa_pages_migrated 539 616 numa_pte_updates 8433 13374 Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1537552141-27815-5-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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3f9672baaa |
sched/numa: Reset scan rate whenever task moves across nodes
Currently task scan rate is reset when NUMA balancer migrates the task to a different node. If NUMA balancer initiates a swap, reset is only applicable to the task that initiates the swap. Similarly no scan rate reset is done if the task is migrated across nodes by traditional load balancer. Instead move the scan reset to the migrate_task_rq. This ensures the task moved out of its preferred node, either gets back to its preferred node quickly or finds a new preferred node. Doing so, would be fair to all tasks migrating across nodes. Specjbb2005 results (8 warehouses) Higher bops are better 2 Socket - 2 Node Haswell - X86 JVMS Prev Current %Change 4 200668 203370 1.3465 1 321791 328431 2.06345 2 Socket - 4 Node Power8 - PowerNV JVMS Prev Current %Change 1 204848 206070 0.59654 2 Socket - 2 Node Power9 - PowerNV JVMS Prev Current %Change 4 188098 188386 0.153112 1 200351 201566 0.606436 4 Socket - 4 Node Power7 - PowerVM JVMS Prev Current %Change 8 58145.9 59157.4 1.73959 1 103798 105495 1.63491 Some events stats before and after applying the patch. perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 13,912,183 13,825,492 migrations 1,155,931 1,152,509 faults 367,139 371,948 cache-misses 54,240,196,814 55,654,206,041 sched:sched_move_numa 1,571 1,856 sched:sched_stick_numa 9 4 sched:sched_swap_numa 463 428 migrate:mm_migrate_pages 703 898 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 50155 57146 numa_hint_faults_local 45264 51612 numa_hit 239652 238164 numa_huge_pte_updates 36 16 numa_interleave 68 63 numa_local 239576 238085 numa_other 76 79 numa_pages_migrated 680 883 numa_pte_updates 71146 67540 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 3,156,720 3,288,525 migrations 30,354 38,652 faults 97,261 111,678 cache-misses 12,400,026,826 12,111,197,376 sched:sched_move_numa 4 900 sched:sched_stick_numa 0 0 sched:sched_swap_numa 1 5 migrate:mm_migrate_pages 20 714 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 272 18572 numa_hint_faults_local 186 14850 numa_hit 71362 73197 numa_huge_pte_updates 0 11 numa_interleave 23 25 numa_local 71299 73138 numa_other 63 59 numa_pages_migrated 2 712 numa_pte_updates 0 24021 perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 8,606,824 8,451,543 migrations 155,352 202,804 faults 301,409 310,024 cache-misses 157,759,224 253,522,507 sched:sched_move_numa 168 213 sched:sched_stick_numa 0 0 sched:sched_swap_numa 3 2 migrate:mm_migrate_pages 125 88 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 4650 11830 numa_hint_faults_local 3946 11301 numa_hit 90489 90038 numa_huge_pte_updates 0 0 numa_interleave 892 855 numa_local 90034 89796 numa_other 455 242 numa_pages_migrated 124 88 numa_pte_updates 4818 12039 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 2,113,167 2,049,153 migrations 10,533 11,405 faults 142,727 162,309 cache-misses 5,594,192 7,203,343 sched:sched_move_numa 10 22 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 0 migrate:mm_migrate_pages 6 1 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 744 1693 numa_hint_faults_local 584 1669 numa_hit 25551 25177 numa_huge_pte_updates 0 0 numa_interleave 263 194 numa_local 25302 24993 numa_other 249 184 numa_pages_migrated 6 1 numa_pte_updates 744 1577 perf stats 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 101,227,352 94,515,937 migrations 4,151,829 4,203,554 faults 745,233 832,697 cache-misses 224,669,561,766 226,248,698,331 sched:sched_move_numa 617 1,730 sched:sched_stick_numa 2 14 sched:sched_swap_numa 187 432 migrate:mm_migrate_pages 316 1,398 vmstat 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 24195 80079 numa_hint_faults_local 21639 68620 numa_hit 238331 241187 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 238331 241186 numa_other 0 1 numa_pages_migrated 204 1347 numa_pte_updates 24561 80729 perf stats 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 62,738,978 63,704,961 migrations 562,702 573,404 faults 228,465 230,878 cache-misses 75,778,067,952 76,568,222,781 sched:sched_move_numa 648 509 sched:sched_stick_numa 13 31 sched:sched_swap_numa 137 182 migrate:mm_migrate_pages 733 541 vmstat 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 10281 8501 numa_hint_faults_local 3242 2960 numa_hit 36338 35526 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 36338 35526 numa_other 0 0 numa_pages_migrated 706 539 numa_pte_updates 10176 8433 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1537552141-27815-4-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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1327237a59 |
sched/numa: Pass destination CPU as a parameter to migrate_task_rq
This additional parameter (new_cpu) is used later for identifying if task migration is across nodes. No functional change. Specjbb2005 results (8 warehouses) Higher bops are better 2 Socket - 2 Node Haswell - X86 JVMS Prev Current %Change 4 203353 200668 -1.32036 1 328205 321791 -1.95427 2 Socket - 4 Node Power8 - PowerNV JVMS Prev Current %Change 1 214384 204848 -4.44809 2 Socket - 2 Node Power9 - PowerNV JVMS Prev Current %Change 4 188553 188098 -0.241311 1 196273 200351 2.07772 4 Socket - 4 Node Power7 - PowerVM JVMS Prev Current %Change 8 57581.2 58145.9 0.980702 1 103468 103798 0.318939 Brings out the variance between different specjbb2005 runs. Some events stats before and after applying the patch. perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 13,941,377 13,912,183 migrations 1,157,323 1,155,931 faults 382,175 367,139 cache-misses 54,993,823,500 54,240,196,814 sched:sched_move_numa 2,005 1,571 sched:sched_stick_numa 14 9 sched:sched_swap_numa 529 463 migrate:mm_migrate_pages 1,573 703 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 67099 50155 numa_hint_faults_local 58456 45264 numa_hit 240416 239652 numa_huge_pte_updates 18 36 numa_interleave 65 68 numa_local 240339 239576 numa_other 77 76 numa_pages_migrated 1574 680 numa_pte_updates 77182 71146 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 3,176,453 3,156,720 migrations 30,238 30,354 faults 87,869 97,261 cache-misses 12,544,479,391 12,400,026,826 sched:sched_move_numa 23 4 sched:sched_stick_numa 0 0 sched:sched_swap_numa 6 1 migrate:mm_migrate_pages 10 20 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 236 272 numa_hint_faults_local 201 186 numa_hit 72293 71362 numa_huge_pte_updates 0 0 numa_interleave 26 23 numa_local 72233 71299 numa_other 60 63 numa_pages_migrated 8 2 numa_pte_updates 0 0 perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 8,478,820 8,606,824 migrations 171,323 155,352 faults 307,499 301,409 cache-misses 240,353,599 157,759,224 sched:sched_move_numa 214 168 sched:sched_stick_numa 0 0 sched:sched_swap_numa 4 3 migrate:mm_migrate_pages 89 125 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 5301 4650 numa_hint_faults_local 4745 3946 numa_hit 92943 90489 numa_huge_pte_updates 0 0 numa_interleave 899 892 numa_local 92345 90034 numa_other 598 455 numa_pages_migrated 88 124 numa_pte_updates 5505 4818 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 2,066,172 2,113,167 migrations 11,076 10,533 faults 149,544 142,727 cache-misses 10,398,067 5,594,192 sched:sched_move_numa 43 10 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 0 migrate:mm_migrate_pages 6 6 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 3552 744 numa_hint_faults_local 3347 584 numa_hit 25611 25551 numa_huge_pte_updates 0 0 numa_interleave 213 263 numa_local 25583 25302 numa_other 28 249 numa_pages_migrated 6 6 numa_pte_updates 3535 744 perf stats 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 99,358,136 101,227,352 migrations 4,041,607 4,151,829 faults 749,653 745,233 cache-misses 225,562,543,251 224,669,561,766 sched:sched_move_numa 771 617 sched:sched_stick_numa 14 2 sched:sched_swap_numa 204 187 migrate:mm_migrate_pages 1,180 316 vmstat 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 27409 24195 numa_hint_faults_local 20677 21639 numa_hit 239988 238331 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 239983 238331 numa_other 5 0 numa_pages_migrated 1016 204 numa_pte_updates 27916 24561 perf stats 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 60,899,307 62,738,978 migrations 544,668 562,702 faults 270,834 228,465 cache-misses 74,543,455,635 75,778,067,952 sched:sched_move_numa 735 648 sched:sched_stick_numa 25 13 sched:sched_swap_numa 174 137 migrate:mm_migrate_pages 816 733 vmstat 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 11059 10281 numa_hint_faults_local 4733 3242 numa_hit 41384 36338 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 41383 36338 numa_other 1 0 numa_pages_migrated 815 706 numa_pte_updates 11323 10176 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1537552141-27815-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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a4739eca44 |
sched/numa: Stop multiple tasks from moving to the CPU at the same time
Task migration under NUMA balancing can happen in parallel. More than one task might choose to migrate to the same CPU at the same time. This can result in: - During task swap, choosing a task that was not part of the evaluation. - During task swap, task which just got moved into its preferred node, moving to a completely different node. - During task swap, task failing to move to the preferred node, will have to wait an extra interval for the next migrate opportunity. - During task movement, multiple task movements can cause load imbalance. This problem is more likely if there are more cores per node or more nodes in the system. Use a per run-queue variable to check if NUMA-balance is active on the run-queue. Specjbb2005 results (8 warehouses) Higher bops are better 2 Socket - 2 Node Haswell - X86 JVMS Prev Current %Change 4 200194 203353 1.57797 1 311331 328205 5.41995 2 Socket - 4 Node Power8 - PowerNV JVMS Prev Current %Change 1 197654 214384 8.46429 2 Socket - 2 Node Power9 - PowerNV JVMS Prev Current %Change 4 192605 188553 -2.10379 1 213402 196273 -8.02664 4 Socket - 4 Node Power7 - PowerVM JVMS Prev Current %Change 8 52227.1 57581.2 10.2516 1 102529 103468 0.915838 There is a regression on power 9 box. If we look at the details, that box has a sudden jump in cache-misses with this patch. All other parameters seem to be pointing towards NUMA consolidation. perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 13,345,784 13,941,377 migrations 1,127,820 1,157,323 faults 374,736 382,175 cache-misses 55,132,054,603 54,993,823,500 sched:sched_move_numa 1,923 2,005 sched:sched_stick_numa 52 14 sched:sched_swap_numa 595 529 migrate:mm_migrate_pages 1,932 1,573 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 60605 67099 numa_hint_faults_local 51804 58456 numa_hit 239945 240416 numa_huge_pte_updates 14 18 numa_interleave 60 65 numa_local 239865 240339 numa_other 80 77 numa_pages_migrated 1931 1574 numa_pte_updates 67823 77182 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After cs 3,016,467 3,176,453 migrations 37,326 30,238 faults 115,342 87,869 cache-misses 11,692,155,554 12,544,479,391 sched:sched_move_numa 965 23 sched:sched_stick_numa 8 0 sched:sched_swap_numa 35 6 migrate:mm_migrate_pages 1,168 10 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Haswell - X86 Event Before After numa_hint_faults 16286 236 numa_hint_faults_local 11863 201 numa_hit 112482 72293 numa_huge_pte_updates 33 0 numa_interleave 20 26 numa_local 112419 72233 numa_other 63 60 numa_pages_migrated 1144 8 numa_pte_updates 32859 0 perf stats 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 8,629,724 8,478,820 migrations 221,052 171,323 faults 308,661 307,499 cache-misses 135,574,913 240,353,599 sched:sched_move_numa 147 214 sched:sched_stick_numa 0 0 sched:sched_swap_numa 2 4 migrate:mm_migrate_pages 64 89 vmstat 8th warehouse Multi JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 11481 5301 numa_hint_faults_local 10968 4745 numa_hit 89773 92943 numa_huge_pte_updates 0 0 numa_interleave 1116 899 numa_local 89220 92345 numa_other 553 598 numa_pages_migrated 62 88 numa_pte_updates 11694 5505 perf stats 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After cs 2,272,887 2,066,172 migrations 12,206 11,076 faults 163,704 149,544 cache-misses 4,801,186 10,398,067 sched:sched_move_numa 44 43 sched:sched_stick_numa 0 0 sched:sched_swap_numa 0 0 migrate:mm_migrate_pages 17 6 vmstat 8th warehouse Single JVM 2 Socket - 2 Node Power9 - PowerNV Event Before After numa_hint_faults 2261 3552 numa_hint_faults_local 1993 3347 numa_hit 25726 25611 numa_huge_pte_updates 0 0 numa_interleave 239 213 numa_local 25498 25583 numa_other 228 28 numa_pages_migrated 17 6 numa_pte_updates 2266 3535 perf stats 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 117,980,962 99,358,136 migrations 3,950,220 4,041,607 faults 736,979 749,653 cache-misses 224,976,072,879 225,562,543,251 sched:sched_move_numa 504 771 sched:sched_stick_numa 50 14 sched:sched_swap_numa 239 204 migrate:mm_migrate_pages 1,260 1,180 vmstat 8th warehouse Multi JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 18293 27409 numa_hint_faults_local 11969 20677 numa_hit 240854 239988 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 240851 239983 numa_other 3 5 numa_pages_migrated 1190 1016 numa_pte_updates 18106 27916 perf stats 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After cs 61,053,158 60,899,307 migrations 551,586 544,668 faults 244,174 270,834 cache-misses 74,326,766,973 74,543,455,635 sched:sched_move_numa 344 735 sched:sched_stick_numa 24 25 sched:sched_swap_numa 140 174 migrate:mm_migrate_pages 568 816 vmstat 8th warehouse Single JVM 4 Socket - 4 Node Power7 - PowerVM Event Before After numa_hint_faults 6461 11059 numa_hint_faults_local 2283 4733 numa_hit 35661 41384 numa_huge_pte_updates 0 0 numa_interleave 0 0 numa_local 35661 41383 numa_other 0 1 numa_pages_migrated 568 815 numa_pte_updates 6518 11323 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Jirka Hladky <jhladky@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1537552141-27815-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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7477a3504e |
sched/numa: Remove unused numa_stats::nr_running field
nr_running in struct numa_stats is not used anywhere in the code. Remove it. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1535548752-4434-3-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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d90707ebeb |
sched/numa: Remove unused code from update_numa_stats()
With:
commit
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Chris Redpath
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4ad3831a9d |
sched/fair: Don't move tasks to lower capacity CPUs unless necessary
When lower capacity CPUs are load balancing and considering to pull something from a higher capacity group, we should not pull tasks from a CPU with only one task running as this is guaranteed to impede progress for that task. If there is more than one task running, load balance in the higher capacity group would have already made any possible moves to resolve imbalance and we should make better use of system compute capacity by moving a task if we still have more than one running. Signed-off-by: Chris Redpath <chris.redpath@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-11-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Valentin Schneider
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757ffdd705 |
sched/fair: Set rq->rd->overload when misfit
Idle balance is a great opportunity to pull a misfit task. However,
there are scenarios where misfit tasks are present but idle balance is
prevented by the overload flag.
A good example of this is a workload of n identical tasks. Let's suppose
we have a 2+2 Arm big.LITTLE system. We then spawn 4 fairly
CPU-intensive tasks - for the sake of simplicity let's say they are just
CPU hogs, even when running on big CPUs.
They are identical tasks, so on an SMP system they should all end at
(roughly) the same time. However, in our case the LITTLE CPUs are less
performing than the big CPUs, so tasks running on the LITTLEs will have
a longer completion time.
This means that the big CPUs will complete their work earlier, at which
point they should pull the tasks from the LITTLEs. What we want to
happen is summarized as follows:
a,b,c,d are our CPU-hogging tasks _ signifies idling
LITTLE_0 | a a a a _ _
LITTLE_1 | b b b b _ _
---------|-------------
big_0 | c c c c a a
big_1 | d d d d b b
^
^
Tasks end on the big CPUs, idle balance happens
and the misfit tasks are pulled straight away
This however won't happen, because currently the overload flag is only
set when there is any CPU that has more than one runnable task - which
may very well not be the case here if our CPU-hogging workload is all
there is to run.
As such, this commit sets the overload flag in update_sg_lb_stats when
a group is flagged as having a misfit task.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-10-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Valentin Schneider
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e90c8fe15a |
sched/fair: Wrap rq->rd->overload accesses with READ/WRITE_ONCE()
This variable can be read and set locklessly within update_sd_lb_stats(). As such, READ/WRITE_ONCE() are added to make sure nothing terribly wrong can happen because of the compiler. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-9-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Valentin Schneider
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dbbad71944 |
sched/fair: Change 'prefer_sibling' type to bool
This variable is entirely local to update_sd_lb_stats, so we can safely change its type and slightly clean up its initialisation. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-7-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Valentin Schneider
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5fbdfae522 |
sched/fair: Kick nohz balance if rq->misfit_task_load
There already are a few conditions in nohz_kick_needed() to ensure a nohz kick is triggered, but they are not enough for some misfit task scenarios. Excluding asym packing, those are: - rq->nr_running >=2: Not relevant here because we are running a misfit task, it needs to be migrated regardless and potentially through active balance. - sds->nr_busy_cpus > 1: If there is only the misfit task being run on a group of low capacity CPUs, this will be evaluated to False. - rq->cfs.h_nr_running >=1 && check_cpu_capacity(): Not relevant here, misfit task needs to be migrated regardless of rt/IRQ pressure As such, this commit adds an rq->misfit_task_load condition to trigger a nohz kick. The idea to kick a nohz balance for misfit tasks originally came from Leo Yan <leo.yan@linaro.org>, and a similar patch was submitted for the Android Common Kernel - see: https://lists.linaro.org/pipermail/eas-dev/2016-September/000551.html Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-6-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Morten Rasmussen
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cad68e552e |
sched/fair: Consider misfit tasks when load-balancing
On asymmetric CPU capacity systems load intensive tasks can end up on CPUs that don't suit their compute demand. In this scenarios 'misfit' tasks should be migrated to CPUs with higher compute capacity to ensure better throughput. group_misfit_task indicates this scenario, but tweaks to the load-balance code are needed to make the migrations happen. Misfit balancing only makes sense between a source group of lower per-CPU capacity and destination group of higher compute capacity. Otherwise, misfit balancing is ignored. group_misfit_task has lowest priority so any imbalance due to overload is dealt with first. The modifications are: 1. Only pick a group containing misfit tasks as the busiest group if the destination group has higher capacity and has spare capacity. 2. When the busiest group is a 'misfit' group, skip the usual average load and group capacity checks. 3. Set the imbalance for 'misfit' balancing sufficiently high for a task to be pulled ignoring average load. 4. Pick the CPU with the highest misfit load as the source CPU. 5. If the misfit task is alone on the source CPU, go for active balancing. Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-5-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Morten Rasmussen
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e3d6d0cb66 |
sched/fair: Add sched_group per-CPU max capacity
The current sg->min_capacity tracks the lowest per-CPU compute capacity available in the sched_group when rt/irq pressure is taken into account. Minimum capacity isn't the ideal metric for tracking if a sched_group needs offloading to another sched_group for some scenarios, e.g. a sched_group with multiple CPUs if only one is under heavy pressure. Tracking maximum capacity isn't perfect either but a better choice for some situations as it indicates that the sched_group definitely compute capacity constrained either due to rt/irq pressure on all CPUs or asymmetric CPU capacities (e.g. big.LITTLE). Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-4-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Morten Rasmussen
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3b1baa6496 |
sched/fair: Add 'group_misfit_task' load-balance type
To maximize throughput in systems with asymmetric CPU capacities (e.g.
ARM big.LITTLE) load-balancing has to consider task and CPU utilization
as well as per-CPU compute capacity when load-balancing in addition to
the current average load based load-balancing policy. Tasks with high
utilization that are scheduled on a lower capacity CPU need to be
identified and migrated to a higher capacity CPU if possible to maximize
throughput.
To implement this additional policy an additional group_type
(load-balance scenario) is added: 'group_misfit_task'. This represents
scenarios where a sched_group has one or more tasks that are not
suitable for its per-CPU capacity. 'group_misfit_task' is only considered
if the system is not overloaded or imbalanced ('group_imbalanced' or
'group_overloaded').
Identifying misfit tasks requires the rq lock to be held. To avoid
taking remote rq locks to examine source sched_groups for misfit tasks,
each CPU is responsible for tracking misfit tasks themselves and update
the rq->misfit_task flag. This means checking task utilization when
tasks are scheduled and on sched_tick.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-3-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Morten Rasmussen
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df054e8445 |
sched/topology: Add static_key for asymmetric CPU capacity optimizations
The existing asymmetric CPU capacity code should cause minimal overhead for others. Putting it behind a static_key, it has been done for SMT optimizations, would make it easier to extend and improve without causing harm to others moving forward. Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: gaku.inami.xh@renesas.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1530699470-29808-2-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Randy Dunlap
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882a78a9f3 |
sched/fair: Fix kernel-doc notation warning
Fix kernel-doc warning for missing 'flags' parameter description:
../kernel/sched/fair.c:3371: warning: Function parameter or member 'flags' not described in 'attach_entity_load_avg'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes:
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Vincent Guittot
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bb3485c8ac |
sched/fair: Fix load_balance redo for !imbalance
It can happen that load_balance() finds a busiest group and then a busiest rq but the calculated imbalance is in fact 0. In such situation, detach_tasks() returns immediately and lets the flag LBF_ALL_PINNED set. The busiest CPU is then wrongly assumed to have pinned tasks and removed from the load balance mask. then, we redo a load balance without the busiest CPU. This creates wrong load balance situation and generates wrong task migration. If the calculated imbalance is 0, it's useless to try to find a busiest rq as no task will be migrated and we can return immediately. This situation can happen with heterogeneous system or smp system when RT tasks are decreasing the capacity of some CPUs. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: jhugo@codeaurora.org Link: http://lkml.kernel.org/r/1536306664-29827-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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287cdaac57 |
sched/fair: Fix scale_rt_capacity() for SMT
Since commit: |
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Steve Muckle
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d0cdb3ce88 |
sched/fair: Fix vruntime_normalized() for remote non-migration wakeup
When a task which previously ran on a given CPU is remotely queued to
wake up on that same CPU, there is a period where the task's state is
TASK_WAKING and its vruntime is not normalized. This is not accounted
for in vruntime_normalized() which will cause an error in the task's
vruntime if it is switched from the fair class during this time.
For example if it is boosted to RT priority via rt_mutex_setprio(),
rq->min_vruntime will not be subtracted from the task's vruntime but
it will be added again when the task returns to the fair class. The
task's vruntime will have been erroneously doubled and the effective
priority of the task will be reduced.
Note this will also lead to inflation of all vruntimes since the doubled
vruntime value will become the rq's min_vruntime when other tasks leave
the rq. This leads to repeated doubling of the vruntime and priority
penalty.
Fix this by recognizing a WAKING task's vruntime as normalized only if
sched_remote_wakeup is true. This indicates a migration, in which case
the vruntime would have been normalized in migrate_task_rq_fair().
Based on a similar patch from John Dias <joaodias@google.com>.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Steve Muckle <smuckle@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Redpath <Chris.Redpath@arm.com>
Cc: John Dias <joaodias@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel de Dios <migueldedios@google.com>
Cc: Morten Rasmussen <Morten.Rasmussen@arm.com>
Cc: Patrick Bellasi <Patrick.Bellasi@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: kernel-team@android.com
Fixes:
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Vincent Guittot
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12b04875d6 |
sched/pelt: Fix update_blocked_averages() for RT and DL classes
update_blocked_averages() is called to periodiccally decay the stalled load of idle CPUs and to sync all loads before running load balance. When cfs rq is idle, it trigs a load balance during pick_next_task_fair() in order to potentially pull tasks and to use this newly idle CPU. This load balance happens whereas prev task from another class has not been put and its utilization updated yet. This may lead to wrongly account running time as idle time for RT or DL classes. Test that no RT or DL task is running when updating their utilization in update_blocked_averages(). We still update RT and DL utilization instead of simply skipping them to make sure that all metrics are synced when used during load balance. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: |
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Linus Torvalds
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958f338e96 |
Merge branch 'l1tf-final' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Merge L1 Terminal Fault fixes from Thomas Gleixner:
"L1TF, aka L1 Terminal Fault, is yet another speculative hardware
engineering trainwreck. It's a hardware vulnerability which allows
unprivileged speculative access to data which is available in the
Level 1 Data Cache when the page table entry controlling the virtual
address, which is used for the access, has the Present bit cleared or
other reserved bits set.
If an instruction accesses a virtual address for which the relevant
page table entry (PTE) has the Present bit cleared or other reserved
bits set, then speculative execution ignores the invalid PTE and loads
the referenced data if it is present in the Level 1 Data Cache, as if
the page referenced by the address bits in the PTE was still present
and accessible.
While this is a purely speculative mechanism and the instruction will
raise a page fault when it is retired eventually, the pure act of
loading the data and making it available to other speculative
instructions opens up the opportunity for side channel attacks to
unprivileged malicious code, similar to the Meltdown attack.
While Meltdown breaks the user space to kernel space protection, L1TF
allows to attack any physical memory address in the system and the
attack works across all protection domains. It allows an attack of SGX
and also works from inside virtual machines because the speculation
bypasses the extended page table (EPT) protection mechanism.
The assoicated CVEs are: CVE-2018-3615, CVE-2018-3620, CVE-2018-3646
The mitigations provided by this pull request include:
- Host side protection by inverting the upper address bits of a non
present page table entry so the entry points to uncacheable memory.
- Hypervisor protection by flushing L1 Data Cache on VMENTER.
- SMT (HyperThreading) control knobs, which allow to 'turn off' SMT
by offlining the sibling CPU threads. The knobs are available on
the kernel command line and at runtime via sysfs
- Control knobs for the hypervisor mitigation, related to L1D flush
and SMT control. The knobs are available on the kernel command line
and at runtime via sysfs
- Extensive documentation about L1TF including various degrees of
mitigations.
Thanks to all people who have contributed to this in various ways -
patches, review, testing, backporting - and the fruitful, sometimes
heated, but at the end constructive discussions.
There is work in progress to provide other forms of mitigations, which
might be less horrible performance wise for a particular kind of
workloads, but this is not yet ready for consumption due to their
complexity and limitations"
* 'l1tf-final' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
x86/microcode: Allow late microcode loading with SMT disabled
tools headers: Synchronise x86 cpufeatures.h for L1TF additions
x86/mm/kmmio: Make the tracer robust against L1TF
x86/mm/pat: Make set_memory_np() L1TF safe
x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert
x86/speculation/l1tf: Invert all not present mappings
cpu/hotplug: Fix SMT supported evaluation
KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry
x86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry
x86/speculation: Simplify sysfs report of VMX L1TF vulnerability
Documentation/l1tf: Remove Yonah processors from not vulnerable list
x86/KVM/VMX: Don't set l1tf_flush_l1d from vmx_handle_external_intr()
x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d
x86: Don't include linux/irq.h from asm/hardirq.h
x86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d
x86/irq: Demote irq_cpustat_t::__softirq_pending to u16
x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush()
x86/KVM/VMX: Replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond'
x86/KVM/VMX: Don't set l1tf_flush_l1d to true from vmx_l1d_flush()
cpu/hotplug: detect SMT disabled by BIOS
...
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Thomas Gleixner
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f2701b77bb |
Merge 4.18-rc7 into master to pick up the KVM dependcy
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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Srikar Dronamraju
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b6a60cf36d |
sched/numa: Move task_numa_placement() closer to numa_migrate_preferred()
numa_migrate_preferred() is called periodically or when task preferred node changes. Preferred node evaluations happen once per scan sequence. If the scan completion happens just after the periodic NUMA migration, then we try to migrate to the preferred node and the preferred node might change, needing another node migration. Avoid this by checking for scan sequence completion only when checking for periodic migration. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25862.6 26158.1 1.14258 1 74357 72725 -2.19482 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 117019 113992 -2.58 1 179095 174947 -2.31 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 449.46 770.77 615.22 101.70 numa01.sh Sys: 132.72 208.17 170.46 24.96 numa01.sh User: 39185.26 60290.89 50066.76 6807.84 numa02.sh Real: 60.85 61.79 61.28 0.37 numa02.sh Sys: 15.34 24.71 21.08 3.61 numa02.sh User: 5204.41 5249.85 5231.21 17.60 numa03.sh Real: 785.50 916.97 840.77 44.98 numa03.sh Sys: 108.08 133.60 119.43 8.82 numa03.sh User: 61422.86 70919.75 64720.87 3310.61 numa04.sh Real: 429.57 587.37 480.80 57.40 numa04.sh Sys: 240.61 321.97 290.84 33.58 numa04.sh User: 34597.65 40498.99 37079.48 2060.72 numa05.sh Real: 392.09 431.25 414.65 13.82 numa05.sh Sys: 229.41 372.48 297.54 53.14 numa05.sh User: 33390.86 34697.49 34222.43 556.42 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 424.63 566.18 498.12 59.26 23.50% numa01.sh Sys: 160.19 256.53 208.98 37.02 -18.4% numa01.sh User: 37320.00 46225.58 42001.57 3482.45 19.20% numa02.sh Real: 60.17 62.47 60.91 0.85 0.607% numa02.sh Sys: 15.30 22.82 17.04 2.90 23.70% numa02.sh User: 5202.13 5255.51 5219.08 20.14 0.232% numa03.sh Real: 823.91 844.89 833.86 8.46 0.828% numa03.sh Sys: 130.69 148.29 140.47 6.21 -14.9% numa03.sh User: 62519.15 64262.20 63613.38 620.05 1.740% numa04.sh Real: 515.30 603.74 548.56 30.93 -12.3% numa04.sh Sys: 459.73 525.48 489.18 21.63 -40.5% numa04.sh User: 40561.96 44919.18 42047.87 1526.85 -11.8% numa05.sh Real: 396.58 454.37 421.13 19.71 -1.53% numa05.sh Sys: 208.72 422.02 348.90 73.60 -14.7% numa05.sh User: 33124.08 36109.35 34846.47 1089.74 -1.79% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-20-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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f35678b6a1 |
sched/numa: Use group_weights to identify if migration degrades locality
On NUMA_BACKPLANE and NUMA_GLUELESS_MESH systems, tasks/memory should be consolidated to the closest group of nodes. In such a case, relying on group_fault metric may not always help to consolidate. There can always be a case where a node closer to the preferred node may have lesser faults than a node further away from the preferred node. In such a case, moving to node with more faults might avoid numa consolidation. Using group_weight would help to consolidate task/memory around the preferred_node. While here, to be on the conservative side, don't override migrate thread degrades locality logic for CPU_NEWLY_IDLE load balancing. Note: Similar problems exist with should_numa_migrate_memory and will be dealt separately. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25645.4 25960 1.22 1 72142 73550 1.95 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 110199 120071 8.958 1 176303 176249 -0.03 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 490.04 774.86 596.26 96.46 numa01.sh Sys: 151.52 242.88 184.82 31.71 numa01.sh User: 41418.41 60844.59 48776.09 6564.27 numa02.sh Real: 60.14 62.94 60.98 1.00 numa02.sh Sys: 16.11 30.77 21.20 5.28 numa02.sh User: 5184.33 5311.09 5228.50 44.24 numa03.sh Real: 790.95 856.35 826.41 24.11 numa03.sh Sys: 114.93 118.85 117.05 1.63 numa03.sh User: 60990.99 64959.28 63470.43 1415.44 numa04.sh Real: 434.37 597.92 504.87 59.70 numa04.sh Sys: 237.63 397.40 289.74 55.98 numa04.sh User: 34854.87 41121.83 38572.52 2615.84 numa05.sh Real: 386.77 448.90 417.22 22.79 numa05.sh Sys: 149.23 379.95 303.04 79.55 numa05.sh User: 32951.76 35959.58 34562.18 1034.05 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 493.19 672.88 597.51 59.38 -0.20% numa01.sh Sys: 150.09 245.48 207.76 34.26 -11.0% numa01.sh User: 41928.51 53779.17 48747.06 3901.39 0.059% numa02.sh Real: 60.63 62.87 61.22 0.83 -0.39% numa02.sh Sys: 16.64 27.97 20.25 4.06 4.691% numa02.sh User: 5222.92 5309.60 5254.03 29.98 -0.48% numa03.sh Real: 821.52 902.15 863.60 32.41 -4.30% numa03.sh Sys: 112.04 130.66 118.35 7.08 -1.09% numa03.sh User: 62245.16 69165.14 66443.04 2450.32 -4.47% numa04.sh Real: 414.53 519.57 476.25 37.00 6.009% numa04.sh Sys: 181.84 335.67 280.41 54.07 3.327% numa04.sh User: 33924.50 39115.39 37343.78 1934.26 3.290% numa05.sh Real: 408.30 441.45 417.90 12.05 -0.16% numa05.sh Sys: 233.41 381.60 295.58 57.37 2.523% numa05.sh User: 33301.31 35972.50 34335.19 938.94 0.661% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-16-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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30619c89b1 |
sched/numa: Update the scan period without holding the numa_group lock
The metrics for updating scan periods are local or task specific. Currently this update happens under the numa_group lock, which seems unnecessary. Hence move this update outside the lock. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25355.9 25645.4 1.141 1 72812 72142 -0.92 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-15-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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2d4056fafa |
sched/numa: Remove numa_has_capacity()
task_numa_find_cpu() helps to find the CPU to swap/move the task to. It's guarded by numa_has_capacity(). However node not having capacity shouldn't deter a task swapping if it helps NUMA placement. Further load_too_imbalanced(), which evaluates possibilities of move/swap, provides similar checks as numa_has_capacity. Hence remove numa_has_capacity() to enhance possibilities of task swapping even if load is imbalanced. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25657.9 25804.1 0.569 1 74435 73413 -1.37 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-13-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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0ad4e3dfe6 |
sched/numa: Modify migrate_swap() to accept additional parameters
There are checks in migrate_swap_stop() that check if the task/CPU combination is as per migrate_swap_arg before migrating. However atleast one of the two tasks to be swapped by migrate_swap() could have migrated to a completely different CPU before updating the migrate_swap_arg. The new CPU where the task is currently running could be a different node too. If the task has migrated, numa balancer might end up placing a task in a wrong node. Instead of achieving node consolidation, it may end up spreading the load across nodes. To avoid that pass the CPUs as additional parameters. While here, place migrate_swap under CONFIG_NUMA_BALANCING. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25377.3 25226.6 -0.59 1 72287 73326 1.437 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-10-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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10864a9e22 |
sched/numa: Remove unused task_capacity from 'struct numa_stats'
The task_capacity field in 'struct numa_stats' is redundant. Also move nr_running for better packing within the struct. No functional changes. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25308.6 25377.3 0.271 1 72964 72287 -0.92 Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Rik van Riel <riel@surriel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-9-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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0ee7e74dc0 |
sched/numa: Skip nodes that are at 'hoplimit'
When comparing two nodes at a distance of 'hoplimit', we should consider nodes only up to 'hoplimit'. Currently we also consider nodes at 'oplimit' distance too. Hence two nodes at a distance of 'hoplimit' will have same groupweight. Fix this by skipping nodes at hoplimit. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25375.3 25308.6 -0.26 1 72617 72964 0.477 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 113372 108750 -4.07684 1 177403 183115 3.21979 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 478.45 565.90 515.11 30.87 numa01.sh Sys: 207.79 271.04 232.94 21.33 numa01.sh User: 39763.93 47303.12 43210.73 2644.86 numa02.sh Real: 60.00 61.46 60.78 0.49 numa02.sh Sys: 15.71 25.31 20.69 3.42 numa02.sh User: 5175.92 5265.86 5235.97 32.82 numa03.sh Real: 776.42 834.85 806.01 23.22 numa03.sh Sys: 114.43 128.75 121.65 5.49 numa03.sh User: 60773.93 64855.25 62616.91 1576.39 numa04.sh Real: 456.93 511.95 482.91 20.88 numa04.sh Sys: 178.09 460.89 356.86 94.58 numa04.sh User: 36312.09 42553.24 39623.21 2247.96 numa05.sh Real: 393.98 493.48 436.61 35.59 numa05.sh Sys: 164.49 329.15 265.87 61.78 numa05.sh User: 33182.65 36654.53 35074.51 1187.71 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 414.64 819.20 556.08 147.70 -7.36% numa01.sh Sys: 77.52 205.04 139.40 52.05 67.10% numa01.sh User: 37043.24 61757.88 45517.48 9290.38 -5.06% numa02.sh Real: 60.80 63.32 61.63 0.88 -1.37% numa02.sh Sys: 17.35 39.37 25.71 7.33 -19.5% numa02.sh User: 5213.79 5374.73 5268.90 55.09 -0.62% numa03.sh Real: 780.09 948.64 831.43 63.02 -3.05% numa03.sh Sys: 104.96 136.92 116.31 11.34 4.591% numa03.sh User: 60465.42 73339.78 64368.03 4700.14 -2.72% numa04.sh Real: 412.60 681.92 521.29 96.64 -7.36% numa04.sh Sys: 210.32 314.10 251.77 37.71 41.74% numa04.sh User: 34026.38 45581.20 38534.49 4198.53 2.825% numa05.sh Real: 394.79 439.63 411.35 16.87 6.140% numa05.sh Sys: 238.32 330.09 292.31 38.32 -9.04% numa05.sh User: 33456.45 34876.07 34138.62 609.45 2.741% While there is a regression with this change, this change is needed from a correctness perspective. Also it helps consolidation as seen from perf bench output. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-8-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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f03bb6760b |
sched/numa: Use task faults only if numa_group is not yet set up
When numa_group faults are available, task_numa_placement only uses numa_group faults to evaluate preferred node. However it still accounts task faults and even evaluates the preferred node just based on task faults just to discard it in favour of preferred node chosen on the basis of numa_group. Instead use task faults only if numa_group is not set. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25549.6 25215.7 -1.30 1 73190 72107 -1.47 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 113437 113372 -0.05 1 196130 177403 -9.54 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 506.35 794.46 599.06 104.26 numa01.sh Sys: 150.37 223.56 195.99 24.94 numa01.sh User: 43450.69 61752.04 49281.50 6635.33 numa02.sh Real: 60.33 62.40 61.31 0.90 numa02.sh Sys: 18.12 31.66 24.28 5.89 numa02.sh User: 5203.91 5325.32 5260.29 49.98 numa03.sh Real: 696.47 853.62 745.80 57.28 numa03.sh Sys: 85.68 123.71 97.89 13.48 numa03.sh User: 55978.45 66418.63 59254.94 3737.97 numa04.sh Real: 444.05 514.83 497.06 26.85 numa04.sh Sys: 230.39 375.79 316.23 48.58 numa04.sh User: 35403.12 41004.10 39720.80 2163.08 numa05.sh Real: 423.09 460.41 439.57 13.92 numa05.sh Sys: 287.38 480.15 369.37 68.52 numa05.sh User: 34732.12 38016.80 36255.85 1070.51 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 478.45 565.90 515.11 30.87 16.29% numa01.sh Sys: 207.79 271.04 232.94 21.33 -15.8% numa01.sh User: 39763.93 47303.12 43210.73 2644.86 14.04% numa02.sh Real: 60.00 61.46 60.78 0.49 0.871% numa02.sh Sys: 15.71 25.31 20.69 3.42 17.35% numa02.sh User: 5175.92 5265.86 5235.97 32.82 0.464% numa03.sh Real: 776.42 834.85 806.01 23.22 -7.47% numa03.sh Sys: 114.43 128.75 121.65 5.49 -19.5% numa03.sh User: 60773.93 64855.25 62616.91 1576.39 -5.36% numa04.sh Real: 456.93 511.95 482.91 20.88 2.930% numa04.sh Sys: 178.09 460.89 356.86 94.58 -11.3% numa04.sh User: 36312.09 42553.24 39623.21 2247.96 0.246% numa05.sh Real: 393.98 493.48 436.61 35.59 0.677% numa05.sh Sys: 164.49 329.15 265.87 61.78 38.92% numa05.sh User: 33182.65 36654.53 35074.51 1187.71 3.368% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-6-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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8cd45eee43 |
sched/numa: Set preferred_node based on best_cpu
Currently preferred node is set to dst_nid which is the last node in the iteration whose group weight or task weight is greater than the current node. However it doesn't guarantee that dst_nid has the numa capacity to move. It also doesn't guarantee that dst_nid has the best_cpu which is the CPU/node ideal for node migration. Lets consider faults on a 4 node system with group weight numbers in different nodes being in 0 < 1 < 2 < 3 proportion. Consider the task is running on 3 and 0 is its preferred node but its capacity is full. Consider nodes 1, 2 and 3 have capacity. Then the task should be migrated to node 1. Currently the task gets moved to node 2. env.dst_nid points to the last node whose faults were greater than current node. Modify to set the preferred node based of best_cpu. Earlier setting preferred node was skipped if nr_active_nodes is 1. This could result in the task being moved out of the preferred node to a random node during regular load balancing. Also while modifying task_numa_migrate(), use sched_setnuma to set preferred node. This ensures out numa accounting is correct. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25122.9 25549.6 1.698 1 73850 73190 -0.89 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 105930 113437 7.08676 1 178624 196130 9.80047 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 435.78 653.81 534.58 83.20 numa01.sh Sys: 121.93 187.18 145.90 23.47 numa01.sh User: 37082.81 51402.80 43647.60 5409.75 numa02.sh Real: 60.64 61.63 61.19 0.40 numa02.sh Sys: 14.72 25.68 19.06 4.03 numa02.sh User: 5210.95 5266.69 5233.30 20.82 numa03.sh Real: 746.51 808.24 780.36 23.88 numa03.sh Sys: 97.26 108.48 105.07 4.28 numa03.sh User: 58956.30 61397.05 60162.95 1050.82 numa04.sh Real: 465.97 519.27 484.81 19.62 numa04.sh Sys: 304.43 359.08 334.68 20.64 numa04.sh User: 37544.16 41186.15 39262.44 1314.91 numa05.sh Real: 411.57 457.20 433.29 16.58 numa05.sh Sys: 230.05 435.48 339.95 67.58 numa05.sh User: 33325.54 36896.31 35637.84 1222.64 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 506.35 794.46 599.06 104.26 -10.76% numa01.sh Sys: 150.37 223.56 195.99 24.94 -25.55% numa01.sh User: 43450.69 61752.04 49281.50 6635.33 -11.43% numa02.sh Real: 60.33 62.40 61.31 0.90 -0.195% numa02.sh Sys: 18.12 31.66 24.28 5.89 -21.49% numa02.sh User: 5203.91 5325.32 5260.29 49.98 -0.513% numa03.sh Real: 696.47 853.62 745.80 57.28 4.6339% numa03.sh Sys: 85.68 123.71 97.89 13.48 7.3347% numa03.sh User: 55978.45 66418.63 59254.94 3737.97 1.5323% numa04.sh Real: 444.05 514.83 497.06 26.85 -2.464% numa04.sh Sys: 230.39 375.79 316.23 48.58 5.8343% numa04.sh User: 35403.12 41004.10 39720.80 2163.08 -1.153% numa05.sh Real: 423.09 460.41 439.57 13.92 -1.428% numa05.sh Sys: 287.38 480.15 369.37 68.52 -7.964% numa05.sh User: 34732.12 38016.80 36255.85 1070.51 -1.704% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-5-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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5f95ba7a43 |
sched/numa: Simplify load_too_imbalanced()
Currently load_too_imbalance() cares about the slope of imbalance. It doesn't care of the direction of the imbalance. However this may not work if nodes that are being compared have dissimilar capacities. Few nodes might have more cores than other nodes in the system. Also unlike traditional load balance at a NUMA sched domain, multiple requests to migrate from the same source node to same destination node may run in parallel. This can cause huge load imbalance. This is specially true on a larger machines with either large cores per node or more number of nodes in the system. Hence allow move/swap only if the imbalance is going to reduce. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25058.2 25122.9 0.25 1 72950 73850 1.23 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 516.14 892.41 739.84 151.32 numa01.sh Sys: 153.16 192.99 177.70 14.58 numa01.sh User: 39821.04 69528.92 57193.87 10989.48 numa02.sh Real: 60.91 62.35 61.58 0.63 numa02.sh Sys: 16.47 26.16 21.20 3.85 numa02.sh User: 5227.58 5309.61 5265.17 31.04 numa03.sh Real: 739.07 917.73 795.75 64.45 numa03.sh Sys: 94.46 136.08 109.48 14.58 numa03.sh User: 57478.56 72014.09 61764.48 5343.69 numa04.sh Real: 442.61 715.43 530.31 96.12 numa04.sh Sys: 224.90 348.63 285.61 48.83 numa04.sh User: 35836.84 47522.47 40235.41 3985.26 numa05.sh Real: 386.13 489.17 434.94 43.59 numa05.sh Sys: 144.29 438.56 278.80 105.78 numa05.sh User: 33255.86 36890.82 34879.31 1641.98 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 435.78 653.81 534.58 83.20 38.39% numa01.sh Sys: 121.93 187.18 145.90 23.47 21.79% numa01.sh User: 37082.81 51402.80 43647.60 5409.75 31.03% numa02.sh Real: 60.64 61.63 61.19 0.40 0.637% numa02.sh Sys: 14.72 25.68 19.06 4.03 11.22% numa02.sh User: 5210.95 5266.69 5233.30 20.82 0.608% numa03.sh Real: 746.51 808.24 780.36 23.88 1.972% numa03.sh Sys: 97.26 108.48 105.07 4.28 4.197% numa03.sh User: 58956.30 61397.05 60162.95 1050.82 2.661% numa04.sh Real: 465.97 519.27 484.81 19.62 9.385% numa04.sh Sys: 304.43 359.08 334.68 20.64 -14.6% numa04.sh User: 37544.16 41186.15 39262.44 1314.91 2.478% numa05.sh Real: 411.57 457.20 433.29 16.58 0.380% numa05.sh Sys: 230.05 435.48 339.95 67.58 -17.9% numa05.sh User: 33325.54 36896.31 35637.84 1222.64 -2.12% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-4-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Srikar Dronamraju
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305c1fac32 |
sched/numa: Evaluate move once per node
task_numa_compare() helps choose the best CPU to move or swap the selected task. To achieve this task_numa_compare() is called for every CPU in the node. Currently it evaluates if the task can be moved/swapped for each of the CPUs. However the move evaluation is mostly independent of the CPU. Evaluating the move logic once per node, provides scope for simplifying task_numa_compare(). Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25705.2 25058.2 -2.51 1 74433 72950 -1.99 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 96589.6 105930 9.670 1 181830 178624 -1.76 (numbers from v1 based on v4.17-rc5) Testcase Time: Min Max Avg StdDev numa01.sh Real: 440.65 941.32 758.98 189.17 numa01.sh Sys: 183.48 320.07 258.42 50.09 numa01.sh User: 37384.65 71818.14 60302.51 13798.96 numa02.sh Real: 61.24 65.35 62.49 1.49 numa02.sh Sys: 16.83 24.18 21.40 2.60 numa02.sh User: 5219.59 5356.34 5264.03 49.07 numa03.sh Real: 822.04 912.40 873.55 37.35 numa03.sh Sys: 118.80 140.94 132.90 7.60 numa03.sh User: 62485.19 70025.01 67208.33 2967.10 numa04.sh Real: 690.66 872.12 778.49 65.44 numa04.sh Sys: 459.26 563.03 494.03 42.39 numa04.sh User: 51116.44 70527.20 58849.44 8461.28 numa05.sh Real: 418.37 562.28 525.77 54.27 numa05.sh Sys: 299.45 481.00 392.49 64.27 numa05.sh User: 34115.09 41324.02 39105.30 2627.68 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 516.14 892.41 739.84 151.32 2.587% numa01.sh Sys: 153.16 192.99 177.70 14.58 45.42% numa01.sh User: 39821.04 69528.92 57193.87 10989.48 5.435% numa02.sh Real: 60.91 62.35 61.58 0.63 1.477% numa02.sh Sys: 16.47 26.16 21.20 3.85 0.943% numa02.sh User: 5227.58 5309.61 5265.17 31.04 -0.02% numa03.sh Real: 739.07 917.73 795.75 64.45 9.776% numa03.sh Sys: 94.46 136.08 109.48 14.58 21.39% numa03.sh User: 57478.56 72014.09 61764.48 5343.69 8.813% numa04.sh Real: 442.61 715.43 530.31 96.12 46.79% numa04.sh Sys: 224.90 348.63 285.61 48.83 72.97% numa04.sh User: 35836.84 47522.47 40235.41 3985.26 46.26% numa05.sh Real: 386.13 489.17 434.94 43.59 20.88% numa05.sh Sys: 144.29 438.56 278.80 105.78 40.77% numa05.sh User: 33255.86 36890.82 34879.31 1641.98 12.11% Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1529514181-9842-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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2e62c4743a |
sched/fair: Remove #ifdefs from scale_rt_capacity()
Reuse cpu_util_irq() that has been defined for schedutil and set irq util to 0 when !CONFIG_IRQ_TIME_ACCOUNTING. But the compiler is not able to optimize the sequence (at least with aarch64 GCC 7.2.1): free *= (max - irq); free /= max; when irq is fixed to 0 Add a new inline function scale_irq_capacity() that will scale utilization when irq is accounted. Reuse this funciton in schedutil which applies similar formula. Suggested-by: Ingo Molnar <mingo@redhat.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: rjw@rjwysocki.net Link: http://lkml.kernel.org/r/1532001606-6689-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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bbb62c0b02 |
sched/core: Remove the rt_avg code
rt_avg is not used anywhere anymore, so we can remove all related code. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-11-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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523e979d31 |
sched/core: Use PELT for scale_rt_capacity()
The utilization of the CPU by RT, DL and IRQs are now tracked with PELT so we can use these metrics instead of rt_avg to evaluate the remaining capacity available for CFS class. scale_rt_capacity() behavior has been changed and now returns the remaining capacity available for CFS instead of a scaling factor because RT, DL and IRQ provide now absolute utilization value. The same formula as schedutil is used: IRQ util_avg + (1 - IRQ util_avg / max capacity ) * /Sum rq util_avg but the implementation is different because it doesn't return the same value and doesn't benefit of the same optimization. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-10-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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91c27493e7 |
sched/irq: Add IRQ utilization tracking
interrupt and steal time are the only remaining activities tracked by rt_avg. Like for sched classes, we can use PELT to track their average utilization of the CPU. But unlike sched class, we don't track when entering/leaving interrupt; Instead, we take into account the time spent under interrupt context when we update rqs' clock (rq_clock_task). This also means that we have to decay the normal context time and account for interrupt time during the update. That's also important to note that because: rq_clock == rq_clock_task + interrupt time and rq_clock_task is used by a sched class to compute its utilization, the util_avg of a sched class only reflects the utilization of the time spent in normal context and not of the whole time of the CPU. The utilization of interrupt gives an more accurate level of utilization of CPU. The CPU utilization is: avg_irq + (1 - avg_irq / max capacity) * /Sum avg_rq Most of the time, avg_irq is small and neglictible so the use of the approximation CPU utilization = /Sum avg_rq was enough. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-7-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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3727e0e163 |
sched/dl: Add dl_rq utilization tracking
Similarly to what happens with RT tasks, CFS tasks can be preempted by DL tasks and the CFS's utilization might no longer describes the real utilization level. Current DL bandwidth reflects the requirements to meet deadline when tasks are enqueued but not the current utilization of the DL sched class. We track DL class utilization to estimate the system utilization. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-5-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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371bf42732 |
sched/rt: Add rt_rq utilization tracking
schedutil governor relies on cfs_rq's util_avg to choose the OPP when CFS tasks are running. When the CPU is overloaded by CFS and RT tasks, CFS tasks are preempted by RT tasks and in this case util_avg reflects the remaining capacity but not what CFS want to use. In such case, schedutil can select a lower OPP whereas the CPU is overloaded. In order to have a more accurate view of the utilization of the CPU, we track the utilization of RT tasks. Only util_avg is correctly tracked but not load_avg and runnable_load_avg which are useless for rt_rq. rt_rq uses rq_clock_task and cfs_rq uses cfs_rq_clock_task but they are the same at the root group level, so the PELT windows of the util_sum are aligned. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-3-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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c079629862 |
sched/pelt: Move PELT related code in a dedicated file
We want to track rt_rq's utilization as a part of the estimation of the whole rq's utilization. This is necessary because rt tasks can steal utilization to cfs tasks and make them lighter than they are. As we want to use the same load tracking mecanism for both and prevent useless dependency between cfs and rt code, PELT code is moved in a dedicated file. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-2-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Quentin Perret
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8fe5c5a937 |
sched/fair: Fix util_avg of new tasks for asymmetric systems
When a new task wakes-up for the first time, its initial utilization is set to half of the spare capacity of its CPU. The current implementation of post_init_entity_util_avg() uses SCHED_CAPACITY_SCALE directly as a capacity reference. As a result, on a big.LITTLE system, a new task waking up on an idle little CPU will be given ~512 of util_avg, even if the CPU's capacity is significantly less than that. Fix this by computing the spare capacity with arch_scale_cpu_capacity(). Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Link: http://lkml.kernel.org/r/20180612112215.25448-1-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Ingo Molnar
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4520843dfa |
Merge branch 'sched/urgent' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
|
3482d98bbc |
sched/util_est: Fix util_est_dequeue() for throttled cfs_rq
When a cfs_rq is throttled, parent cfs_rq->nr_running is decreased and
everything happens at cfs_rq level. Currently util_est stays unchanged
in such case and it keeps accounting the utilization of throttled tasks.
This can somewhat make sense as we don't dequeue tasks but only throttled
cfs_rq.
If a task of another group is enqueued/dequeued and root cfs_rq becomes
idle during the dequeue, util_est will be cleared whereas it was
accounting util_est of throttled tasks before. So the behavior of util_est
is not always the same regarding throttled tasks and depends of side
activity. Furthermore, util_est will not be updated when the cfs_rq is
unthrottled as everything happens at cfs_rq level. Main results is that
util_est will stay null whereas we now have running tasks. We have to wait
for the next dequeue/enqueue of the previously throttled tasks to get an
up to date util_est.
Remove the assumption that cfs_rq's estimated utilization of a CPU is 0
if there is no running task so the util_est of a task remains until the
latter is dequeued even if its cfs_rq has been throttled.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes:
|
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Xunlei Pang
|
f1d1be8aee |
sched/fair: Advance global expiration when period timer is restarted
When period gets restarted after some idle time, start_cfs_bandwidth() doesn't update the expiration information, expire_cfs_rq_runtime() will see cfs_rq->runtime_expires smaller than rq clock and go to the clock drift logic, wasting needless CPU cycles on the scheduler hot path. Update the global expiration in start_cfs_bandwidth() to avoid frequent expire_cfs_rq_runtime() calls once a new period begins. Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180620101834.24455-2-xlpang@linux.alibaba.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Xunlei Pang
|
512ac999d2 |
sched/fair: Fix bandwidth timer clock drift condition
I noticed that cgroup task groups constantly get throttled even
if they have low CPU usage, this causes some jitters on the response
time to some of our business containers when enabling CPU quotas.
It's very simple to reproduce:
mkdir /sys/fs/cgroup/cpu/test
cd /sys/fs/cgroup/cpu/test
echo 100000 > cpu.cfs_quota_us
echo $$ > tasks
then repeat:
cat cpu.stat | grep nr_throttled # nr_throttled will increase steadily
After some analysis, we found that cfs_rq::runtime_remaining will
be cleared by expire_cfs_rq_runtime() due to two equal but stale
"cfs_{b|q}->runtime_expires" after period timer is re-armed.
The current condition to judge clock drift in expire_cfs_rq_runtime()
is wrong, the two runtime_expires are actually the same when clock
drift happens, so this condtion can never hit. The orginal design was
correctly done by this commit:
|
||
Li RongQing
|
03585a95cd |
sched/fair: Remove stale tg_unthrottle_up() comments
After commit:
|
||
|
Peter Zijlstra
|
ba2591a599 |
sched/smt: Update sched_smt_present at runtime
The static key sched_smt_present is only updated at boot time when SMT siblings have been detected. Booting with maxcpus=1 and bringing the siblings online after boot rebuilds the scheduling domains correctly but does not update the static key, so the SMT code is not enabled. Let the key be updated in the scheduler CPU hotplug code to fix this. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Ingo Molnar <mingo@kernel.org> |
||
Kees Cook
|
6396bb2215 |
treewide: kzalloc() -> kcalloc()
The kzalloc() function has a 2-factor argument form, kcalloc(). This
patch replaces cases of:
kzalloc(a * b, gfp)
with:
kcalloc(a * b, gfp)
as well as handling cases of:
kzalloc(a * b * c, gfp)
with:
kzalloc(array3_size(a, b, c), gfp)
as it's slightly less ugly than:
kzalloc_array(array_size(a, b), c, gfp)
This does, however, attempt to ignore constant size factors like:
kzalloc(4 * 1024, gfp)
though any constants defined via macros get caught up in the conversion.
Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.
The Coccinelle script used for this was:
// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@
(
kzalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
kzalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)
// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@
(
kzalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)
// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@
(
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)
// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@
- kzalloc
+ kcalloc
(
- SIZE * COUNT
+ COUNT, SIZE
, ...)
// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@
(
kzalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)
// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@
(
kzalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kzalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)
// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@
(
kzalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)
// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@
(
kzalloc(C1 * C2 * C3, ...)
|
kzalloc(
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)
// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@
(
kzalloc(sizeof(THING) * C2, ...)
|
kzalloc(sizeof(TYPE) * C2, ...)
|
kzalloc(C1 * C2 * C3, ...)
|
kzalloc(C1 * C2, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- (E1) * E2
+ E1, E2
, ...)
|
- kzalloc
+ kcalloc
(
- (E1) * (E2)
+ E1, E2
, ...)
|
- kzalloc
+ kcalloc
(
- E1 * E2
+ E1, E2
, ...)
)
Signed-off-by: Kees Cook <keescook@chromium.org>
|
||
|
Patrick Bellasi
|
2539fc82aa |
sched/fair: Update util_est before updating schedutil
When a task is enqueued the estimated utilization of a CPU is updated
to better support the selection of the required frequency.
However, schedutil is (implicitly) updated by update_load_avg() which
always happens before util_est_{en,de}queue(), thus potentially
introducing a latency between estimated utilization updates and
frequency selections.
Let's update util_est at the beginning of enqueue_task_fair(),
which will ensure that all schedutil updates will see the most
updated estimated utilization value for a CPU.
Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Steve Muckle <smuckle@google.com>
Fixes:
|
||
Rohit Jain
|
943d355d7f |
sched/core: Distinguish between idle_cpu() calls based on desired effect, introduce available_idle_cpu()
In the following commit:
|
||
|
Mel Gorman
|
1378447598 |
sched/numa: Stagger NUMA balancing scan periods for new threads
Threads share an address space and each can change the protections of the same address space to trap NUMA faults. This is redundant and potentially counter-productive as any thread doing the update will suffice. Potentially only one thread is required but that thread may be idle or it may not have any locality concerns and pick an unsuitable scan rate. This patch uses independent scan period but they are staggered based on the number of address space users when the thread is created. The intent is that threads will avoid scanning at the same time and have a chance to adapt their scan rate later if necessary. This reduces the total scan activity early in the lifetime of the threads. The different in headline performance across a range of machines and workloads is marginal but the system CPU usage is reduced as well as overall scan activity. The following is the time reported by NAS Parallel Benchmark using unbound openmp threads and a D size class: 4.17.0-rc1 4.17.0-rc1 vanilla stagger-v1r1 Time bt.D 442.77 ( 0.00%) 419.70 ( 5.21%) Time cg.D 171.90 ( 0.00%) 180.85 ( -5.21%) Time ep.D 33.10 ( 0.00%) 32.90 ( 0.60%) Time is.D 9.59 ( 0.00%) 9.42 ( 1.77%) Time lu.D 306.75 ( 0.00%) 304.65 ( 0.68%) Time mg.D 54.56 ( 0.00%) 52.38 ( 4.00%) Time sp.D 1020.03 ( 0.00%) 903.77 ( 11.40%) Time ua.D 400.58 ( 0.00%) 386.49 ( 3.52%) Note it's not a universal win but we have no prior knowledge of which thread matters but the number of threads created often exceeds the size of the node when the threads are not bound. However, there is a reducation of overall system CPU usage: 4.17.0-rc1 4.17.0-rc1 vanilla stagger-v1r1 sys-time-bt.D 48.78 ( 0.00%) 48.22 ( 1.15%) sys-time-cg.D 25.31 ( 0.00%) 26.63 ( -5.22%) sys-time-ep.D 1.65 ( 0.00%) 0.62 ( 62.42%) sys-time-is.D 40.05 ( 0.00%) 24.45 ( 38.95%) sys-time-lu.D 37.55 ( 0.00%) 29.02 ( 22.72%) sys-time-mg.D 47.52 ( 0.00%) 34.92 ( 26.52%) sys-time-sp.D 119.01 ( 0.00%) 109.05 ( 8.37%) sys-time-ua.D 51.52 ( 0.00%) 45.13 ( 12.40%) NUMA scan activity is also reduced: NUMA alloc local 1042828 1342670 NUMA base PTE updates 140481138 93577468 NUMA huge PMD updates 272171 180766 NUMA page range updates 279832690 186129660 NUMA hint faults 1395972 1193897 NUMA hint local faults 877925 855053 NUMA hint local percent 62 71 NUMA pages migrated 12057909 9158023 Similar observations are made for other thread-intensive workloads. System CPU usage is lower even though the headline gains in performance tend to be small. For example, specjbb 2005 shows almost no difference in performance but scan activity is reduced by a third on a 4-socket box. I didn't find a workload (thread intensive or otherwise) that suffered badly. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20180504154109.mvrha2qo5wdl65vr@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Ingo Molnar
|
dfd5c3ea64 |
Linux 4.17-rc5
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAlr4xw8eHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGNYoH/1d5zyMpVJVUKZ0K LuEctCGby1PjSvSOhmMuxFVagFAqfBJXmwWTeohLfLG48r/Yk0AsZQ5HH13/8baj k/T8UgUvKZKustndCRp+joQ3Pa1ZpcIFaWRvB8pKFCefJ/F/Lj4B4X1HYI7vLq0K /ZBXUdy3ry0lcVuypnaARYAb2O7l/nyZIjZ3FhiuyymWe7Jpo+G7VK922LOMSX/y VYFZCWa8nxN+yFhO0ao9X5k7ggIiUrEBtbfNrk19VtAn0hx+OYKW2KfJK/eHNey/ CKrOT+KAxU8VU29AEIbYzlL3yrQmULcEoIDiqJ/6m5m6JwsEbP6EqQHs0TiuQFpq A0MO9rw= =yjUP -----END PGP SIGNATURE----- Merge tag 'v4.17-rc5' into sched/core, to pick up fixes and dependencies Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
66e1c94db3 |
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/pti updates from Thomas Gleixner:
"A mixed bag of fixes and updates for the ghosts which are hunting us.
The scheduler fixes have been pulled into that branch to avoid
conflicts.
- A set of fixes to address a khread_parkme() race which caused lost
wakeups and loss of state.
- A deadlock fix for stop_machine() solved by moving the wakeups
outside of the stopper_lock held region.
- A set of Spectre V1 array access restrictions. The possible
problematic spots were discuvered by Dan Carpenters new checks in
smatch.
- Removal of an unused file which was forgotten when the rest of that
functionality was removed"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Remove unused file
perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr
perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver
perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map()
perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_*
perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[]
sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[]
sched/core: Fix possible Spectre-v1 indexing for sched_prio_to_weight[]
sched/core: Introduce set_special_state()
kthread, sched/wait: Fix kthread_parkme() completion issue
kthread, sched/wait: Fix kthread_parkme() wait-loop
sched/fair: Fix the update of blocked load when newly idle
stop_machine, sched: Fix migrate_swap() vs. active_balance() deadlock
|
||
|
Mel Gorman
|
789ba28013 |
Revert "sched/numa: Delay retrying placement for automatic NUMA balance after wake_affine()"
This reverts commit
|
||
|
Viresh Kumar
|
c976a862ba |
sched/fair: Avoid calling sync_entity_load_avg() unnecessarily
Call sync_entity_load_avg() directly from find_idlest_cpu() instead of select_task_rq_fair(), as that's where we need to use task's utilization value. And call sync_entity_load_avg() only after making sure sched domain spans over one of the allowed CPUs for the task. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/cd019d1753824c81130eae7b43e2bbcec47cc1ad.1524738578.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Viresh Kumar
|
f1d88b4468 |
sched/fair: Rearrange select_task_rq_fair() to optimize it
Rearrange select_task_rq_fair() a bit to avoid executing some conditional statements in few specific code-paths. That gets rid of the goto as well. This shouldn't result in any functional changes. Tested-by: Rohit Jain <rohit.k.jain@oracle.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/20831b8d237bf3a20e4e328286f678b425ff04c9.1524738578.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Vincent Guittot
|
457be908c8 |
sched/fair: Fix the update of blocked load when newly idle
With commit: |
||
Davidlohr Bueso
|
adcc8da885 |
sched/core: Simplify helpers for rq clock update skip requests
By renaming the functions we can get rid of the skip parameter and have better code redability. It makes zero sense to have things such as: rq_clock_skip_update(rq, false) When the skip request is in fact not going to happen. Ever. Rename things such that we end up with: rq_clock_skip_update(rq) rq_clock_cancel_skipupdate(rq) Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20180404161539.nhadkff2aats74jh@linux-n805 Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Patrick Bellasi
|
d519329f72 |
sched/fair: Update util_est only on util_avg updates
The estimated utilization of a task is currently updated every time the task is dequeued. However, to keep overheads under control, PELT signals are effectively updated at maximum once every 1ms. Thus, for really short running tasks, it can happen that their util_avg value has not been updates since their last enqueue. If such tasks are also frequently running tasks (e.g. the kind of workload generated by hackbench) it can also happen that their util_avg is updated only every few activations. This means that updating util_est at every dequeue potentially introduces not necessary overheads and it's also conceptually wrong if the util_avg signal has never been updated during a task activation. Let's introduce a throttling mechanism on task's util_est updates to sync them with util_avg updates. To make the solution memory efficient, both in terms of space and load/store operations, we encode a synchronization flag into the LSB of util_est.enqueued. This makes util_est an even values only metric, which is still considered good enough for its purpose. The synchronization bit is (re)set by __update_load_avg_se() once the PELT signal of a task has been updated during its last activation. Such a throttling mechanism allows to keep under control util_est overheads in the wakeup hot path, thus making it a suitable mechanism which can be enabled also on high-intensity workload systems. Thus, this now switches on by default the estimation utilization scheduler feature. Suggested-by: Chris Redpath <chris.redpath@arm.com> Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@android.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/20180309095245.11071-5-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
|
f9be3e5961 |
sched/fair: Use util_est in LB and WU paths
When the scheduler looks at the CPU utilization, the current PELT value for a CPU is returned straight away. In certain scenarios this can have undesired side effects on task placement. For example, since the task utilization is decayed at wakeup time, when a long sleeping big task is enqueued it does not add immediately a significant contribution to the target CPU. As a result we generate a race condition where other tasks can be placed on the same CPU while it is still considered relatively empty. In order to reduce this kind of race conditions, this patch introduces the required support to integrate the usage of the CPU's estimated utilization in the wakeup path, via cpu_util_wake(), as well as in the load-balance path, via cpu_util() which is used by update_sg_lb_stats(). The estimated utilization of a CPU is defined to be the maximum between its PELT's utilization and the sum of the estimated utilization (at previous dequeue time) of all the tasks currently RUNNABLE on that CPU. This allows to properly represent the spare capacity of a CPU which, for example, has just got a big task running since a long sleep period. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@android.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/20180309095245.11071-3-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Patrick Bellasi
|
7f65ea42eb |
sched/fair: Add util_est on top of PELT
The util_avg signal computed by PELT is too variable for some use-cases.
For example, a big task waking up after a long sleep period will have its
utilization almost completely decayed. This introduces some latency before
schedutil will be able to pick the best frequency to run a task.
The same issue can affect task placement. Indeed, since the task
utilization is already decayed at wakeup, when the task is enqueued in a
CPU, this can result in a CPU running a big task as being temporarily
represented as being almost empty. This leads to a race condition where
other tasks can be potentially allocated on a CPU which just started to run
a big task which slept for a relatively long period.
Moreover, the PELT utilization of a task can be updated every [ms], thus
making it a continuously changing value for certain longer running
tasks. This means that the instantaneous PELT utilization of a RUNNING
task is not really meaningful to properly support scheduler decisions.
For all these reasons, a more stable signal can do a better job of
representing the expected/estimated utilization of a task/cfs_rq.
Such a signal can be easily created on top of PELT by still using it as
an estimator which produces values to be aggregated on meaningful
events.
This patch adds a simple implementation of util_est, a new signal built on
top of PELT's util_avg where:
util_est(task) = max(task::util_avg, f(task::util_avg@dequeue))
This allows to remember how big a task has been reported by PELT in its
previous activations via f(task::util_avg@dequeue), which is the new
_task_util_est(struct task_struct*) function added by this patch.
If a task should change its behavior and it runs longer in a new
activation, after a certain time its util_est will just track the
original PELT signal (i.e. task::util_avg).
The estimated utilization of cfs_rq is defined only for root ones.
That's because the only sensible consumer of this signal are the
scheduler and schedutil when looking for the overall CPU utilization
due to FAIR tasks.
For this reason, the estimated utilization of a root cfs_rq is simply
defined as:
util_est(cfs_rq) = max(cfs_rq::util_avg, cfs_rq::util_est::enqueued)
where:
cfs_rq::util_est::enqueued = sum(_task_util_est(task))
for each RUNNABLE task on that root cfs_rq
It's worth noting that the estimated utilization is tracked only for
objects of interests, specifically:
- Tasks: to better support tasks placement decisions
- root cfs_rqs: to better support both tasks placement decisions as
well as frequencies selection
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Steve Muckle <smuckle@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@android.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/20180309095245.11071-2-patrick.bellasi@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Vincent Guittot
|
31e77c93e4 |
sched/fair: Update blocked load when newly idle
When NEWLY_IDLE load balance is not triggered, we might need to update the blocked load anyway. We can kick an ilb so an idle CPU will take care of updating blocked load or we can try to update them locally before entering idle. In the latter case, we reuse part of the nohz_idle_balance. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: brendan.jackman@arm.com Cc: dietmar.eggemann@arm.com Cc: morten.rasmussen@foss.arm.com Cc: valentin.schneider@arm.com Link: http://lkml.kernel.org/r/1518622006-16089-4-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Peter Zijlstra
|
47ea54121e |
sched/fair: Move idle_balance()
We're going to want to call nohz_idle_balance() or parts thereof from idle_balance(). Since we already have a forward declaration of idle_balance() move it down such that it's below nohz_idle_balance() avoiding the need for a forward declaration for that. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Peter Zijlstra
|
dd707247ab |
sched/nohz: Merge CONFIG_NO_HZ_COMMON blocks
Now that we have two back-to-back NO_HZ_COMMON blocks, merge them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Peter Zijlstra
|
af3fe03c56 |
sched/fair: Move rebalance_domains()
This pure code movement results in two #ifdef CONFIG_NO_HZ_COMMON sections landing next to each other. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
63928384fa |
sched/nohz: Optimize nohz_idle_balance()
Avoid calling update_blocked_averages() when it does not in fact have any by re-using/extending update_nohz_stats(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
|
1936c53ce8 |
sched/fair: Reduce the periodic update duration
Instead of using the cfs_rq_is_decayed() which monitors all *_avg and *_sum, we create a cfs_rq_has_blocked() which only takes care of util_avg and load_avg. We are only interested by these 2 values which are decaying faster than the *_sum so we can stop the periodic update earlier. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: brendan.jackman@arm.com Cc: dietmar.eggemann@arm.com Cc: morten.rasmussen@foss.arm.com Cc: valentin.schneider@arm.com Link: http://lkml.kernel.org/r/1518517879-2280-3-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
|
f643ea2207 |
sched/nohz: Stop NOHZ stats when decayed
Stopped the periodic update of blocked load when all idle CPUs have fully decayed. We introduce a new nohz.has_blocked that reflect if some idle CPUs has blocked load that have to be periodiccally updated. nohz.has_blocked is set everytime that a Idle CPU can have blocked load and it is then clear when no more blocked load has been detected during an update. We don't need atomic operation but only to make cure of the right ordering when updating nohz.idle_cpus_mask and nohz.has_blocked. Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: brendan.jackman@arm.com Cc: dietmar.eggemann@arm.com Cc: morten.rasmussen@foss.arm.com Cc: valentin.schneider@arm.com Link: http://lkml.kernel.org/r/1518517879-2280-2-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
ea14b57e8a |
sched/cpufreq: Provide migration hint
It was suggested that a migration hint might be usefull for the CPU-freq governors. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
00357f5ec5 |
sched/nohz: Clean up nohz enter/exit
The primary observation is that nohz enter/exit is always from the
current CPU, therefore NOHZ_TICK_STOPPED does not in fact need to be
an atomic.
Secondary is that we appear to have 2 nearly identical hooks in the
nohz enter code, set_cpu_sd_state_idle() and
nohz_balance_enter_idle(). Fold the whole set_cpu_sd_state thing into
nohz_balance_{enter,exit}_idle.
Removes an atomic op from both enter and exit paths.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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|
Peter Zijlstra
|
e022e0d38a |
sched/fair: Update blocked load from NEWIDLE
Since we already iterate CPUs looking for work on NEWIDLE, use this iteration to age the blocked load. If the domain for which this is done completely spand the idle set, we can push the ILB based aging forward. Suggested-by: Brendan Jackman <brendan.jackman@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Peter Zijlstra
|
a4064fb614 |
sched/fair: Add NOHZ stats balancing
Teach the idle balancer about the need to update statistics which have a different periodicity from regular balancing. Suggested-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
4550487a99 |
sched/fair: Restructure nohz_balance_kick()
The current: if (nohz_kick_needed()) nohz_balancer_kick() is pointless complexity, fold them into a single call and avoid the various conditions at the call site. When we introduce multiple different needs to kick the ilb, the above construct also becomes a problem. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Peter Zijlstra
|
b7031a02ec |
sched/fair: Add NOHZ_STATS_KICK
Split the NOHZ idle balancer into doing two separate actions: - update blocked load statistic - actually load-balance Since the latter requires the former, ensure this happens. For now always tag both bits at the same time. Prepares for a future where we can toggle only the STATS bit. Suggested-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
a22e47a4e3 |
sched/core: Convert nohz_flags to atomic_t
Using atomic_t allows us to use the more flexible bitops provided there. Also its smaller. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Norbert Manthey
|
13a453c241 |
sched/fair: Add ';' after label attributes
Due to using GCC defines for configuration, some labels might be unused in certain configurations. While adding a __maybe_unused to the label is fine in general, the line has to be terminated with ';'. This is also reflected in the GCC documentation, but GCC parsed the previous variant without an error message. This has been spotted while compiling with goto-cc, the compiler for the CPROVER tool suite. Signed-off-by: Norbert Manthey <nmanthey@amazon.de> Signed-off-by: Michael Tautschnig <tautschn@amazon.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1519717660-16157-1-git-send-email-nmanthey@amazon.de Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Ingo Molnar
|
325ea10c08 |
sched/headers: Simplify and clean up header usage in the scheduler
Do the following cleanups and simplifications: - sched/sched.h already includes <asm/paravirt.h>, so no need to include it in sched/core.c again. - order the <linux/sched/*.h> headers alphabetically - add all <linux/sched/*.h> headers to kernel/sched/sched.h - remove all unnecessary includes from the .c files that are already included in kernel/sched/sched.h. Finally, make all scheduler .c files use a single common header: #include "sched.h" ... which now contains a union of the relied upon headers. This makes the various .c files easier to read and easier to handle. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Ingo Molnar
|
97fb7a0a89 |
sched: Clean up and harmonize the coding style of the scheduler code base
A good number of small style inconsistencies have accumulated
in the scheduler core, so do a pass over them to harmonize
all these details:
- fix speling in comments,
- use curly braces for multi-line statements,
- remove unnecessary parentheses from integer literals,
- capitalize consistently,
- remove stray newlines,
- add comments where necessary,
- remove invalid/unnecessary comments,
- align structure definitions and other data types vertically,
- add missing newlines for increased readability,
- fix vertical tabulation where it's misaligned,
- harmonize preprocessor conditional block labeling
and vertical alignment,
- remove line-breaks where they uglify the code,
- add newline after local variable definitions,
No change in functionality:
md5:
1191fa0a890cfa8132156d2959d7e9e2 built-in.o.before.asm
1191fa0a890cfa8132156d2959d7e9e2 built-in.o.after.asm
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Frederic Weisbecker
|
d84b31313e |
sched/isolation: Offload residual 1Hz scheduler tick
When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand any interruption at all, or want to minimize them. The usual boot parameters "nohz_full=" or "isolcpus=nohz" will now outsource these scheduler ticks to the global workqueue so that a housekeeping CPU handles those remotely. The sched_class::task_tick() implementations have been audited and look safe to be called remotely as the target runqueue and its current task are passed in parameter and don't seem to be accessed locally. Note that in the case of using isolcpus, it's still up to the user to affine the global workqueues to the housekeeping CPUs through /sys/devices/virtual/workqueue/cpumask or domains isolation "isolcpus=nohz,domain". Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1519186649-3242-6-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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|
Mel Gorman
|
7347fc87df |
sched/numa: Delay retrying placement for automatic NUMA balance after wake_affine()
If wake_affine() pulls a task to another node for any reason and the node is
no longer preferred then temporarily stop automatic NUMA balancing pulling
the task back. Otherwise, tasks with a strong waker/wakee relationship
may constantly fight automatic NUMA balancing over where a task should
be placed.
Once again netperf is interesting here. The performance barely changes
but automatic NUMA balancing is interesting:
Hmean send-64 354.67 ( 0.00%) 352.15 ( -0.71%)
Hmean send-128 702.91 ( 0.00%) 693.84 ( -1.29%)
Hmean send-256 1350.07 ( 0.00%) 1344.19 ( -0.44%)
Hmean send-1024 5124.38 ( 0.00%) 4941.24 ( -3.57%)
Hmean send-2048 9687.44 ( 0.00%) 9624.45 ( -0.65%)
Hmean send-3312 14577.64 ( 0.00%) 14514.35 ( -0.43%)
Hmean send-4096 16393.62 ( 0.00%) 16488.30 ( 0.58%)
Hmean send-8192 26877.26 ( 0.00%) 26431.63 ( -1.66%)
Hmean send-16384 38683.43 ( 0.00%) 38264.91 ( -1.08%)
Hmean recv-64 354.67 ( 0.00%) 352.15 ( -0.71%)
Hmean recv-128 702.91 ( 0.00%) 693.84 ( -1.29%)
Hmean recv-256 1350.07 ( 0.00%) 1344.19 ( -0.44%)
Hmean recv-1024 5124.38 ( 0.00%) 4941.24 ( -3.57%)
Hmean recv-2048 9687.43 ( 0.00%) 9624.45 ( -0.65%)
Hmean recv-3312 14577.59 ( 0.00%) 14514.35 ( -0.43%)
Hmean recv-4096 16393.55 ( 0.00%) 16488.20 ( 0.58%)
Hmean recv-8192 26876.96 ( 0.00%) 26431.29 ( -1.66%)
Hmean recv-16384 38682.41 ( 0.00%) 38263.94 ( -1.08%)
NUMA alloc hit 1465986
|
||
|
Mel Gorman
|
2c83362734 |
sched/fair: Consider SD_NUMA when selecting the most idle group to schedule on
find_idlest_group() compares a local group with each other group to select
the one that is most idle. When comparing groups in different NUMA domains,
a very slight imbalance is enough to select a remote NUMA node even if the
runnable load on both groups is 0 or close to 0. This ignores the cost of
remote accesses entirely and is a problem when selecting the CPU for a
newly forked task to run on. This is problematic when a forking server
is almost guaranteed to run on a remote node incurring numerous remote
accesses and potentially causing automatic NUMA balancing to try migrate
the task back or migrate the data to another node. Similar weirdness is
observed if a basic shell command pipes output to another as each process
in the pipeline is likely to start on different nodes and then get adjusted
later by wake_affine().
This patch adds imbalance to remote domains when considering whether to
select CPUs from remote domains. If the local domain is selected, imbalance
will still be used to try select a CPU from a lower scheduler domain's group
instead of stacking tasks on the same CPU.
A variety of workloads and machines were tested and as expected, there is no
difference on UMA. The difference on NUMA can be dramatic. This is a comparison
of elapsed times running the git regression test suite. It's fork-intensive with
short-lived processes:
4.15.0 4.15.0
noexit-v1r23 sdnuma-v1r23
Elapsed min 1706.06 ( 0.00%) 1435.94 ( 15.83%)
Elapsed mean 1709.53 ( 0.00%) 1436.98 ( 15.94%)
Elapsed stddev 2.16 ( 0.00%) 1.01 ( 53.38%)
Elapsed coeffvar 0.13 ( 0.00%) 0.07 ( 44.54%)
Elapsed max 1711.59 ( 0.00%) 1438.01 ( 15.98%)
4.15.0 4.15.0
noexit-v1r23 sdnuma-v1r23
User 5434.12 5188.41
System 4878.77 3467.09
Elapsed 10259.06 8624.21
That shows a considerable reduction in elapsed times. It's important to
note that automatic NUMA balancing does not affect this load as processes
are too short-lived.
There is also a noticable impact on hackbench such as this example using
processes and pipes:
hackbench-process-pipes
4.15.0 4.15.0
noexit-v1r23 sdnuma-v1r23
Amean 1 1.0973 ( 0.00%) 0.9393 ( 14.40%)
Amean 4 1.3427 ( 0.00%) 1.3730 ( -2.26%)
Amean 7 1.4233 ( 0.00%) 1.6670 ( -17.12%)
Amean 12 3.0250 ( 0.00%) 3.3013 ( -9.13%)
Amean 21 9.0860 ( 0.00%) 9.5343 ( -4.93%)
Amean 30 14.6547 ( 0.00%) 13.2433 ( 9.63%)
Amean 48 22.5447 ( 0.00%) 20.4303 ( 9.38%)
Amean 79 29.2010 ( 0.00%) 26.7853 ( 8.27%)
Amean 110 36.7443 ( 0.00%) 35.8453 ( 2.45%)
Amean 141 45.8533 ( 0.00%) 42.6223 ( 7.05%)
Amean 172 55.1317 ( 0.00%) 50.6473 ( 8.13%)
Amean 203 64.4420 ( 0.00%) 58.3957 ( 9.38%)
Amean 234 73.2293 ( 0.00%) 67.1047 ( 8.36%)
Amean 265 80.5220 ( 0.00%) 75.7330 ( 5.95%)
Amean 296 88.7567 ( 0.00%) 82.1533 ( 7.44%)
It's not a universal win as there are occasions when spreading wide and
quickly is a benefit but it's more of a win than it is a loss. For other
workloads, there is little difference but netperf is interesting. Without
the patch, the server and client starts on different nodes but quickly get
migrated due to wake_affine. Hence, the difference is overall performance
is marginal but detectable:
4.15.0 4.15.0
noexit-v1r23 sdnuma-v1r23
Hmean send-64 349.09 ( 0.00%) 354.67 ( 1.60%)
Hmean send-128 699.16 ( 0.00%) 702.91 ( 0.54%)
Hmean send-256 1316.34 ( 0.00%) 1350.07 ( 2.56%)
Hmean send-1024 5063.99 ( 0.00%) 5124.38 ( 1.19%)
Hmean send-2048 9705.19 ( 0.00%) 9687.44 ( -0.18%)
Hmean send-3312 14359.48 ( 0.00%) 14577.64 ( 1.52%)
Hmean send-4096 16324.20 ( 0.00%) 16393.62 ( 0.43%)
Hmean send-8192 26112.61 ( 0.00%) 26877.26 ( 2.93%)
Hmean send-16384 37208.44 ( 0.00%) 38683.43 ( 3.96%)
Hmean recv-64 349.09 ( 0.00%) 354.67 ( 1.60%)
Hmean recv-128 699.16 ( 0.00%) 702.91 ( 0.54%)
Hmean recv-256 1316.34 ( 0.00%) 1350.07 ( 2.56%)
Hmean recv-1024 5063.99 ( 0.00%) 5124.38 ( 1.19%)
Hmean recv-2048 9705.16 ( 0.00%) 9687.43 ( -0.18%)
Hmean recv-3312 14359.42 ( 0.00%) 14577.59 ( 1.52%)
Hmean recv-4096 16323.98 ( 0.00%) 16393.55 ( 0.43%)
Hmean recv-8192 26111.85 ( 0.00%) 26876.96 ( 2.93%)
Hmean recv-16384 37206.99 ( 0.00%) 38682.41 ( 3.97%)
However, what is very interesting is how automatic NUMA balancing behaves.
Each netperf instance runs long enough for balancing to activate:
NUMA base PTE updates 4620 1473
NUMA huge PMD updates 0 0
NUMA page range updates 4620 1473
NUMA hint faults 4301 1383
NUMA hint local faults 1309 451
NUMA hint local percent 30 32
NUMA pages migrated 1335 491
AutoNUMA cost 21% 6%
There is an unfortunate number of remote faults although tracing indicated
that the vast majority are in shared libraries. However, the tendency to
start tasks on the same node if there is capacity means that there were
far fewer PTE updates and faults incurred overall.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Giovanni Gherdovich <ggherdovich@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180213133730.24064-6-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
|
Peter Zijlstra
|
24d0c1d6e6 |
sched/fair: Do not migrate due to a sync wakeup on exit
When a task exits, it notifies the parent that it has exited. This is a sync wakeup and the exiting task may pull the parent towards the wakers CPU. For simple workloads like using a shell, it was observed that the shell is pulled across nodes by exiting processes. This is daft as the parent may be long-lived and properly placed. This patch special cases a sync wakeup on exit to avoid pulling tasks across nodes. Testing on a range of workloads and machines showed very little differences in performance although there was a small 3% boost on some machines running a shellscript intensive workload (git regression test suite). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Giovanni Gherdovich <ggherdovich@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180213133730.24064-5-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mel Gorman
|
082f764a2f |
sched/fair: Do not migrate on wake_affine_weight() if weights are equal
wake_affine_weight() will consider migrating a task to, or near, the current
CPU if there is a load imbalance. If the CPUs share LLC then either CPU
is valid as a search-for-idle-sibling target and equally appropriate for
stacking two tasks on one CPU if an idle sibling is unavailable. If they do
not share cache then a cross-node migration potentially impacts locality
so while they are equal from a CPU capacity point of view, they are not
equal in terms of memory locality. In either case, it's more appropriate
to migrate only if there is a difference in their effective load.
This patch modifies wake_affine_weight() to only consider migrating a task
if there is a load imbalance for normal wakeups but will allow potential
stacking if the loads are equal and it's a sync wakeup.
For the most part, the different in performance is marginal. For example,
on a 4-socket server running netperf UDP_STREAM on localhost the differences
are as follows:
4.15.0 4.15.0
16rc0 noequal-v1r23
Hmean send-64 355.47 ( 0.00%) 349.50 ( -1.68%)
Hmean send-128 697.98 ( 0.00%) 693.35 ( -0.66%)
Hmean send-256 1328.02 ( 0.00%) 1318.77 ( -0.70%)
Hmean send-1024 5051.83 ( 0.00%) 5051.11 ( -0.01%)
Hmean send-2048 9637.02 ( 0.00%) 9601.34 ( -0.37%)
Hmean send-3312 14355.37 ( 0.00%) 14414.51 ( 0.41%)
Hmean send-4096 16464.97 ( 0.00%) 16301.37 ( -0.99%)
Hmean send-8192 26722.42 ( 0.00%) 26428.95 ( -1.10%)
Hmean send-16384 38137.81 ( 0.00%) 38046.11 ( -0.24%)
Hmean recv-64 355.47 ( 0.00%) 349.50 ( -1.68%)
Hmean recv-128 697.98 ( 0.00%) 693.35 ( -0.66%)
Hmean recv-256 1328.02 ( 0.00%) 1318.77 ( -0.70%)
Hmean recv-1024 5051.83 ( 0.00%) 5051.11 ( -0.01%)
Hmean recv-2048 9636.95 ( 0.00%) 9601.30 ( -0.37%)
Hmean recv-3312 14355.32 ( 0.00%) 14414.48 ( 0.41%)
Hmean recv-4096 16464.74 ( 0.00%) 16301.16 ( -0.99%)
Hmean recv-8192 26721.63 ( 0.00%) 26428.17 ( -1.10%)
Hmean recv-16384 38136.00 ( 0.00%) 38044.88 ( -0.24%)
Stddev send-64 7.30 ( 0.00%) 4.75 ( 34.96%)
Stddev send-128 15.15 ( 0.00%) 22.38 ( -47.66%)
Stddev send-256 13.99 ( 0.00%) 19.14 ( -36.81%)
Stddev send-1024 105.73 ( 0.00%) 67.38 ( 36.27%)
Stddev send-2048 294.57 ( 0.00%) 223.88 ( 24.00%)
Stddev send-3312 302.28 ( 0.00%) 271.74 ( 10.10%)
Stddev send-4096 195.92 ( 0.00%) 121.10 ( 38.19%)
Stddev send-8192 399.71 ( 0.00%) 563.77 ( -41.04%)
Stddev send-16384 1163.47 ( 0.00%) 1103.68 ( 5.14%)
Stddev recv-64 7.30 ( 0.00%) 4.75 ( 34.96%)
Stddev recv-128 15.15 ( 0.00%) 22.38 ( -47.66%)
Stddev recv-256 13.99 ( 0.00%) 19.14 ( -36.81%)
Stddev recv-1024 105.73 ( 0.00%) 67.38 ( 36.27%)
Stddev recv-2048 294.59 ( 0.00%) 223.89 ( 24.00%)
Stddev recv-3312 302.24 ( 0.00%) 271.75 ( 10.09%)
Stddev recv-4096 196.03 ( 0.00%) 121.14 ( 38.20%)
Stddev recv-8192 399.86 ( 0.00%) 563.65 ( -40.96%)
Stddev recv-16384 1163.79 ( 0.00%) 1103.86 ( 5.15%)
The difference in overall performance is marginal but note that most
measurements are less variable. There were similar observations for other
netperf comparisons. hackbench with sockets or threads with processes or
threads showed minor difference with some reduction of migration. tbench
showed only marginal differences that were within the noise. dbench,
regardless of filesystem, showed minor differences all of which are
within noise. Multiple machines, both UMA and NUMA were tested without
any regressions showing up.
The biggest risk with a patch like this is affecting wakeup latencies.
However, the schbench load from Facebook which is very sensitive to wakeup
latency showed a mixed result with mostly improvements in wakeup latency:
4.15.0 4.15.0
16rc0 noequal-v1r23
Lat 50.00th-qrtle-1 38.00 ( 0.00%) 38.00 ( 0.00%)
Lat 75.00th-qrtle-1 49.00 ( 0.00%) 41.00 ( 16.33%)
Lat 90.00th-qrtle-1 52.00 ( 0.00%) 50.00 ( 3.85%)
Lat 95.00th-qrtle-1 54.00 ( 0.00%) 51.00 ( 5.56%)
Lat 99.00th-qrtle-1 63.00 ( 0.00%) 60.00 ( 4.76%)
Lat 99.50th-qrtle-1 66.00 ( 0.00%) 61.00 ( 7.58%)
Lat 99.90th-qrtle-1 78.00 ( 0.00%) 65.00 ( 16.67%)
Lat 50.00th-qrtle-2 38.00 ( 0.00%) 38.00 ( 0.00%)
Lat 75.00th-qrtle-2 42.00 ( 0.00%) 43.00 ( -2.38%)
Lat 90.00th-qrtle-2 46.00 ( 0.00%) 48.00 ( -4.35%)
Lat 95.00th-qrtle-2 49.00 ( 0.00%) 50.00 ( -2.04%)
Lat 99.00th-qrtle-2 55.00 ( 0.00%) 57.00 ( -3.64%)
Lat 99.50th-qrtle-2 58.00 ( 0.00%) 60.00 ( -3.45%)
Lat 99.90th-qrtle-2 65.00 ( 0.00%) 68.00 ( -4.62%)
Lat 50.00th-qrtle-4 41.00 ( 0.00%) 41.00 ( 0.00%)
Lat 75.00th-qrtle-4 45.00 ( 0.00%) 46.00 ( -2.22%)
Lat 90.00th-qrtle-4 50.00 ( 0.00%) 50.00 ( 0.00%)
Lat 95.00th-qrtle-4 54.00 ( 0.00%) 53.00 ( 1.85%)
Lat 99.00th-qrtle-4 61.00 ( 0.00%) 61.00 ( 0.00%)
Lat 99.50th-qrtle-4 65.00 ( 0.00%) 64.00 ( 1.54%)
Lat 99.90th-qrtle-4 76.00 ( 0.00%) 82.00 ( -7.89%)
Lat 50.00th-qrtle-8 48.00 ( 0.00%) 46.00 ( 4.17%)
Lat 75.00th-qrtle-8 55.00 ( 0.00%) 54.00 ( 1.82%)
Lat 90.00th-qrtle-8 60.00 ( 0.00%) 59.00 ( 1.67%)
Lat 95.00th-qrtle-8 63.00 ( 0.00%) 63.00 ( 0.00%)
Lat 99.00th-qrtle-8 71.00 ( 0.00%) 69.00 ( 2.82%)
Lat 99.50th-qrtle-8 74.00 ( 0.00%) 73.00 ( 1.35%)
Lat 99.90th-qrtle-8 98.00 ( 0.00%) 90.00 ( 8.16%)
Lat 50.00th-qrtle-16 56.00 ( 0.00%) 55.00 ( 1.79%)
Lat 75.00th-qrtle-16 68.00 ( 0.00%) 67.00 ( 1.47%)
Lat 90.00th-qrtle-16 77.00 ( 0.00%) 78.00 ( -1.30%)
Lat 95.00th-qrtle-16 82.00 ( 0.00%) 84.00 ( -2.44%)
Lat 99.00th-qrtle-16 90.00 ( 0.00%) 93.00 ( -3.33%)
Lat 99.50th-qrtle-16 93.00 ( 0.00%) 97.00 ( -4.30%)
Lat 99.90th-qrtle-16 110.00 ( 0.00%) 110.00 ( 0.00%)
Lat 50.00th-qrtle-32 68.00 ( 0.00%) 62.00 ( 8.82%)
Lat 75.00th-qrtle-32 90.00 ( 0.00%) 83.00 ( 7.78%)
Lat 90.00th-qrtle-32 110.00 ( 0.00%) 100.00 ( 9.09%)
Lat 95.00th-qrtle-32 122.00 ( 0.00%) 111.00 ( 9.02%)
Lat 99.00th-qrtle-32 145.00 ( 0.00%) 133.00 ( 8.28%)
Lat 99.50th-qrtle-32 154.00 ( 0.00%) 143.00 ( 7.14%)
Lat 99.90th-qrtle-32 2316.00 ( 0.00%) 515.00 ( 77.76%)
Lat 50.00th-qrtle-35 69.00 ( 0.00%) 72.00 ( -4.35%)
Lat 75.00th-qrtle-35 92.00 ( 0.00%) 95.00 ( -3.26%)
Lat 90.00th-qrtle-35 111.00 ( 0.00%) 114.00 ( -2.70%)
Lat 95.00th-qrtle-35 122.00 ( 0.00%) 124.00 ( -1.64%)
Lat 99.00th-qrtle-35 142.00 ( 0.00%) 144.00 ( -1.41%)
Lat 99.50th-qrtle-35 150.00 ( 0.00%) 154.00 ( -2.67%)
Lat 99.90th-qrtle-35 6104.00 ( 0.00%) 5640.00 ( 7.60%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Giovanni Gherdovich <ggherdovich@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180213133730.24064-4-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
|
Mel Gorman
|
eeb6039863 |
sched/fair: Defer calculation of 'prev_eff_load' in wake_affine_weight() until needed
On sync wakeups, the previous CPU effective load may not be used so delay the calculation until it's needed. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Giovanni Gherdovich <ggherdovich@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180213133730.24064-3-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mel Gorman
|
7ebb66a12f |
sched/fair: Avoid an unnecessary lookup of current CPU ID during wake_affine
The only caller of wake_affine() knows the CPU ID. Pass it in instead of rechecking it. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Giovanni Gherdovich <ggherdovich@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180213133730.24064-2-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Vincent Guittot
|
387f77cc82 |
sched/fair: Remove stray space in #ifdef
Remove a useless space in # ifdef and align it with others. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1518512382-29426-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mel Gorman
|
32e839dda3 |
sched/fair: Use a recently used CPU as an idle candidate and the basis for SIS
The select_idle_sibling() (SIS) rewrite in commit:
|
||
|
Mel Gorman
|
806486c377 |
sched/fair: Do not migrate if the prev_cpu is idle
wake_affine_idle() prefers to move a task to the current CPU if the
wakeup is due to an interrupt. The expectation is that the interrupt
data is cache hot and relevant to the waking task as well as avoiding
a search. However, there is no way to determine if there was cache hot
data on the previous CPU that may exceed the interrupt data. Furthermore,
round-robin delivery of interrupts can migrate tasks around a socket where
each CPU is under-utilised. This can interact badly with cpufreq which
makes decisions based on per-cpu data. It has been observed on machines
with HWP that p-states are not boosted to their maximum levels even though
the workload is latency and throughput sensitive.
This patch uses the previous CPU for the task if it's idle and cache-affine
with the current CPU even if the current CPU is idle due to the wakup
being related to the interrupt. This reduces migrations at the cost of
the interrupt data not being cache hot when the task wakes.
A variety of workloads were tested on various machines and no adverse
impact was noticed that was outside noise. dbench on ext4 on UMA showed
roughly 10% reduction in the number of CPU migrations and it is a case
where interrupts are frequent for IO competions. In most cases, the
difference in performance is quite small but variability is often
reduced. For example, this is the result for pgbench running on a UMA
machine with different numbers of clients.
4.15.0-rc9 4.15.0-rc9
baseline waprev-v1
Hmean 1 22096.28 ( 0.00%) 22734.86 ( 2.89%)
Hmean 4 74633.42 ( 0.00%) 75496.77 ( 1.16%)
Hmean 7 115017.50 ( 0.00%) 113030.81 ( -1.73%)
Hmean 12 126209.63 ( 0.00%) 126613.40 ( 0.32%)
Hmean 16 131886.91 ( 0.00%) 130844.35 ( -0.79%)
Stddev 1 636.38 ( 0.00%) 417.11 ( 34.46%)
Stddev 4 614.64 ( 0.00%) 583.24 ( 5.11%)
Stddev 7 542.46 ( 0.00%) 435.45 ( 19.73%)
Stddev 12 173.93 ( 0.00%) 171.50 ( 1.40%)
Stddev 16 671.42 ( 0.00%) 680.30 ( -1.32%)
CoeffVar 1 2.88 ( 0.00%) 1.83 ( 36.26%)
Note that the different in performance is marginal but for low utilisation,
there is less variability.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180130104555.4125-4-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
|
Mel Gorman
|
3b76c4a339 |
sched/fair: Restructure wake_affine*() to return a CPU id
This is a preparation patch that has wake_affine*() return a CPU ID instead of a boolean. The intent is to allow the wake_affine() helpers to be avoided if a decision is already made. This patch has no functional change. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180130104555.4125-3-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mel Gorman
|
89a55f56fd |
sched/fair: Remove unnecessary parameters from wake_affine_idle()
wake_affine_idle() takes parameters it never uses so clean it up. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180130104555.4125-2-mgorman@techsingularity.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Peter Zijlstra
|
2ed41a5502 |
sched/core: Optimize update_stats_*()
These functions are already gated by schedstats_enabled(), there is no point in then issuing another static_branch for every individual update in them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
af8c5e2d60 |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Implement frequency/CPU invariance and OPP selection for
SCHED_DEADLINE (Juri Lelli)
- Tweak the task migration logic for better multi-tasking
workload scalability (Mel Gorman)
- Misc cleanups, fixes and improvements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Make bandwidth enforcement scale-invariant
sched/cpufreq: Move arch_scale_{freq,cpu}_capacity() outside of #ifdef CONFIG_SMP
sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter
sched/cpufreq: Always consider all CPUs when deciding next freq
sched/cpufreq: Split utilization signals
sched/cpufreq: Change the worker kthread to SCHED_DEADLINE
sched/deadline: Move CPU frequency selection triggering points
sched/cpufreq: Use the DEADLINE utilization signal
sched/deadline: Implement "runtime overrun signal" support
sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache
sched/fair: Correct obsolete comment about cpufreq_update_util()
sched/fair: Remove impossible condition from find_idlest_group_cpu()
sched/cpufreq: Don't pass flags to sugov_set_iowait_boost()
sched/cpufreq: Initialize sg_cpu->flags to 0
sched/fair: Consider RT/IRQ pressure in capacity_spare_wake()
sched/fair: Use 'unsigned long' for utilization, consistently
sched/core: Rework and clarify prepare_lock_switch()
sched/fair: Remove unused 'curr' parameter from wakeup_gran
sched/headers: Constify object_is_on_stack()
|
||
|
Peter Zijlstra
|
ce48c14649 |
sched/core: Fix cpu.max vs. cpuhotplug deadlock
Tejun reported the following cpu-hotplug lock (percpu-rwsem) read recursion:
tg_set_cfs_bandwidth()
get_online_cpus()
cpus_read_lock()
cfs_bandwidth_usage_inc()
static_key_slow_inc()
cpus_read_lock()
Reported-by: Tejun Heo <tj@kernel.org>
Tested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180122215328.GP3397@worktop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
Juri Lelli
|
07881166a8 |
sched/deadline: Make bandwidth enforcement scale-invariant
Apply frequency and CPU scale-invariance correction factor to bandwidth enforcement (similar to what we already do to fair utilization tracking). Each delta_exec gets scaled considering current frequency and maximum CPU capacity; which means that the reservation runtime parameter (that need to be specified profiling the task execution at max frequency on biggest capacity core) gets thus scaled accordingly. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Claudio Scordino <claudio@evidence.eu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luca Abeni <luca.abeni@santannapisa.it> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: alessio.balsini@arm.com Cc: bristot@redhat.com Cc: dietmar.eggemann@arm.com Cc: joelaf@google.com Cc: juri.lelli@redhat.com Cc: mathieu.poirier@linaro.org Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: rjw@rjwysocki.net Cc: rostedt@goodmis.org Cc: tkjos@android.com Cc: tommaso.cucinotta@santannapisa.it Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/20171204102325.5110-9-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Juri Lelli
|
7673c8a4c7 |
sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter
The 'sd' parameter is never used in arch_scale_freq_capacity() (and it's hard to see where information coming from scheduling domains might help doing frequency invariance scaling). Remove it; also in anticipation of moving arch_scale_freq_capacity() outside CONFIG_SMP. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: alessio.balsini@arm.com Cc: bristot@redhat.com Cc: claudio@evidence.eu.com Cc: dietmar.eggemann@arm.com Cc: joelaf@google.com Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: mathieu.poirier@linaro.org Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: rjw@rjwysocki.net Cc: rostedt@goodmis.org Cc: tkjos@android.com Cc: tommaso.cucinotta@santannapisa.it Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/20171204102325.5110-7-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mel Gorman
|
7332dec055 |
sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache
If waking from an idle CPU due to an interrupt then it's possible that
the waker task will be pulled to wake on the current CPU. Unfortunately,
depending on the type of interrupt and IRQ configuration, there may not
be a strong relationship between the CPU an interrupt was delivered on
and the CPU a task was running on. For example, the interrupts could all
be delivered to CPUs on one particular node due to the machine topology
or IRQ affinity configuration. Another example is an interrupt for an IO
completion which can be delivered to any CPU where there is no guarantee
the data is either cache hot or even local.
This patch was motivated by the observation that an IO workload was
being pulled cross-node on a frequent basis when IO completed. From a
wakeup latency perspective, it's still useful to know that an idle CPU is
immediately available for use but lets only consider an automatic migration
if the CPUs share cache to limit damage due to NUMA migrations. Migrations
may still occur if wake_affine_weight determines it's appropriate.
These are the throughput results for dbench running on ext4 comparing
4.15-rc3 and this patch on a 2-socket machine where interrupts due to IO
completions can happen on any CPU.
4.15.0-rc3 4.15.0-rc3
vanilla lessmigrate
Hmean 1 854.64 ( 0.00%) 865.01 ( 1.21%)
Hmean 2 1229.60 ( 0.00%) 1274.44 ( 3.65%)
Hmean 4 1591.81 ( 0.00%) 1628.08 ( 2.28%)
Hmean 8 1845.04 ( 0.00%) 1831.80 ( -0.72%)
Hmean 16 2038.61 ( 0.00%) 2091.44 ( 2.59%)
Hmean 32 2327.19 ( 0.00%) 2430.29 ( 4.43%)
Hmean 64 2570.61 ( 0.00%) 2568.54 ( -0.08%)
Hmean 128 2481.89 ( 0.00%) 2499.28 ( 0.70%)
Stddev 1 14.31 ( 0.00%) 5.35 ( 62.65%)
Stddev 2 21.29 ( 0.00%) 11.09 ( 47.92%)
Stddev 4 7.22 ( 0.00%) 6.80 ( 5.92%)
Stddev 8 26.70 ( 0.00%) 9.41 ( 64.76%)
Stddev 16 22.40 ( 0.00%) 20.01 ( 10.70%)
Stddev 32 45.13 ( 0.00%) 44.74 ( 0.85%)
Stddev 64 93.10 ( 0.00%) 93.18 ( -0.09%)
Stddev 128 184.28 ( 0.00%) 177.85 ( 3.49%)
Note the small increase in throughput for low thread counts but also
note that the standard deviation for each sample during the test run is
lower. The throughput figures for dbench can be misleading so the benchmark
is actually modified to time the latency of the processing of one load
file with many samples taken. The difference in latency is
4.15.0-rc3 4.15.0-rc3
vanilla lessmigrate
Amean 1 21.71 ( 0.00%) 21.47 ( 1.08%)
Amean 2 30.89 ( 0.00%) 29.58 ( 4.26%)
Amean 4 47.54 ( 0.00%) 46.61 ( 1.97%)
Amean 8 82.71 ( 0.00%) 82.81 ( -0.12%)
Amean 16 149.45 ( 0.00%) 145.01 ( 2.97%)
Amean 32 265.49 ( 0.00%) 248.43 ( 6.42%)
Amean 64 463.23 ( 0.00%) 463.55 ( -0.07%)
Amean 128 933.97 ( 0.00%) 935.50 ( -0.16%)
Stddev 1 1.58 ( 0.00%) 1.54 ( 2.26%)
Stddev 2 2.84 ( 0.00%) 2.95 ( -4.15%)
Stddev 4 6.78 ( 0.00%) 6.85 ( -0.99%)
Stddev 8 16.85 ( 0.00%) 16.37 ( 2.85%)
Stddev 16 41.59 ( 0.00%) 41.04 ( 1.32%)
Stddev 32 111.05 ( 0.00%) 105.11 ( 5.35%)
Stddev 64 285.94 ( 0.00%) 288.01 ( -0.72%)
Stddev 128 803.39 ( 0.00%) 809.73 ( -0.79%)
It's a small improvement which is not surprising given that migrations that
migrate to a different node as not that common. However, it is noticeable
in the CPU migration statistics which are reduced by 24%.
There was a query for v1 of this patch about NAS so here are the results
for C-class using MPI for parallelisation on the same machine
nas-mpi
4.15.0-rc3 4.15.0-rc3
vanilla noirq
Time cg.C 24.25 ( 0.00%) 23.17 ( 4.45%)
Time ep.C 8.22 ( 0.00%) 8.29 ( -0.85%)
Time ft.C 22.67 ( 0.00%) 20.34 ( 10.28%)
Time is.C 1.42 ( 0.00%) 1.47 ( -3.52%)
Time lu.C 55.62 ( 0.00%) 54.81 ( 1.46%)
Time mg.C 7.93 ( 0.00%) 7.91 ( 0.25%)
4.15.0-rc3 4.15.0-rc3
vanilla noirq-v1r1
User 3799.96 3748.34
System 672.10 626.15
Elapsed 91.91 79.49
lu.C sees a small gain, ft.C a large gain and ep.C and is.C see small
regressions but in terms of absolute time, the difference is small and
likely within run-to-run variance. System CPU usage is slightly reduced.
schbench from Facebook was also requested. This is a bit of a mixed bag but
it's important to note that this workload should not be heavily impacted
by wakeups from interrupt context.
4.15.0-rc3 4.15.0-rc3
vanilla noirq-v1r1
Lat 50.00th-qrtle-1 41.00 ( 0.00%) 41.00 ( 0.00%)
Lat 75.00th-qrtle-1 42.00 ( 0.00%) 42.00 ( 0.00%)
Lat 90.00th-qrtle-1 43.00 ( 0.00%) 44.00 ( -2.33%)
Lat 95.00th-qrtle-1 44.00 ( 0.00%) 46.00 ( -4.55%)
Lat 99.00th-qrtle-1 57.00 ( 0.00%) 58.00 ( -1.75%)
Lat 99.50th-qrtle-1 59.00 ( 0.00%) 59.00 ( 0.00%)
Lat 99.90th-qrtle-1 67.00 ( 0.00%) 78.00 ( -16.42%)
Lat 50.00th-qrtle-2 40.00 ( 0.00%) 51.00 ( -27.50%)
Lat 75.00th-qrtle-2 45.00 ( 0.00%) 56.00 ( -24.44%)
Lat 90.00th-qrtle-2 53.00 ( 0.00%) 59.00 ( -11.32%)
Lat 95.00th-qrtle-2 57.00 ( 0.00%) 61.00 ( -7.02%)
Lat 99.00th-qrtle-2 67.00 ( 0.00%) 71.00 ( -5.97%)
Lat 99.50th-qrtle-2 69.00 ( 0.00%) 74.00 ( -7.25%)
Lat 99.90th-qrtle-2 83.00 ( 0.00%) 77.00 ( 7.23%)
Lat 50.00th-qrtle-4 51.00 ( 0.00%) 51.00 ( 0.00%)
Lat 75.00th-qrtle-4 57.00 ( 0.00%) 56.00 ( 1.75%)
Lat 90.00th-qrtle-4 60.00 ( 0.00%) 59.00 ( 1.67%)
Lat 95.00th-qrtle-4 62.00 ( 0.00%) 62.00 ( 0.00%)
Lat 99.00th-qrtle-4 73.00 ( 0.00%) 72.00 ( 1.37%)
Lat 99.50th-qrtle-4 76.00 ( 0.00%) 74.00 ( 2.63%)
Lat 99.90th-qrtle-4 85.00 ( 0.00%) 78.00 ( 8.24%)
Lat 50.00th-qrtle-8 54.00 ( 0.00%) 58.00 ( -7.41%)
Lat 75.00th-qrtle-8 59.00 ( 0.00%) 62.00 ( -5.08%)
Lat 90.00th-qrtle-8 65.00 ( 0.00%) 66.00 ( -1.54%)
Lat 95.00th-qrtle-8 67.00 ( 0.00%) 70.00 ( -4.48%)
Lat 99.00th-qrtle-8 78.00 ( 0.00%) 79.00 ( -1.28%)
Lat 99.50th-qrtle-8 81.00 ( 0.00%) 80.00 ( 1.23%)
Lat 99.90th-qrtle-8 116.00 ( 0.00%) 83.00 ( 28.45%)
Lat 50.00th-qrtle-16 65.00 ( 0.00%) 64.00 ( 1.54%)
Lat 75.00th-qrtle-16 77.00 ( 0.00%) 71.00 ( 7.79%)
Lat 90.00th-qrtle-16 83.00 ( 0.00%) 82.00 ( 1.20%)
Lat 95.00th-qrtle-16 87.00 ( 0.00%) 87.00 ( 0.00%)
Lat 99.00th-qrtle-16 95.00 ( 0.00%) 96.00 ( -1.05%)
Lat 99.50th-qrtle-16 99.00 ( 0.00%) 103.00 ( -4.04%)
Lat 99.90th-qrtle-16 104.00 ( 0.00%) 122.00 ( -17.31%)
Lat 50.00th-qrtle-32 71.00 ( 0.00%) 73.00 ( -2.82%)
Lat 75.00th-qrtle-32 91.00 ( 0.00%) 92.00 ( -1.10%)
Lat 90.00th-qrtle-32 108.00 ( 0.00%) 107.00 ( 0.93%)
Lat 95.00th-qrtle-32 118.00 ( 0.00%) 115.00 ( 2.54%)
Lat 99.00th-qrtle-32 134.00 ( 0.00%) 129.00 ( 3.73%)
Lat 99.50th-qrtle-32 138.00 ( 0.00%) 133.00 ( 3.62%)
Lat 99.90th-qrtle-32 149.00 ( 0.00%) 146.00 ( 2.01%)
Lat 50.00th-qrtle-39 83.00 ( 0.00%) 81.00 ( 2.41%)
Lat 75.00th-qrtle-39 105.00 ( 0.00%) 102.00 ( 2.86%)
Lat 90.00th-qrtle-39 120.00 ( 0.00%) 119.00 ( 0.83%)
Lat 95.00th-qrtle-39 129.00 ( 0.00%) 128.00 ( 0.78%)
Lat 99.00th-qrtle-39 153.00 ( 0.00%) 149.00 ( 2.61%)
Lat 99.50th-qrtle-39 166.00 ( 0.00%) 156.00 ( 6.02%)
Lat 99.90th-qrtle-39 12304.00 ( 0.00%) 12848.00 ( -4.42%)
When heavily loaded (e.g. 99.50th-qrtle-39 indicates 39 threads), there
are small gains in many cases. Otherwise it depends on the quartile used
where it can be bad -- e.g. 75.00th-qrtle-2. However, even these results
are probably a co-incidence. For this workload, much depends on what node
the threads get placed on and their relative locality and not wakeups from
interrupt context. A larger component on how it behaves would be automatic
NUMA balancing where a fault incurred to measure locality would be a much
larger contributer to latency than the wakeup path.
This is the results from an almost identical machine that happened to run
the same test. They only differ in terms of storage which is irrelevant
for this test.
4.15.0-rc3 4.15.0-rc3
vanilla noirq-v1r1
Lat 50.00th-qrtle-1 41.00 ( 0.00%) 41.00 ( 0.00%)
Lat 75.00th-qrtle-1 42.00 ( 0.00%) 42.00 ( 0.00%)
Lat 90.00th-qrtle-1 44.00 ( 0.00%) 43.00 ( 2.27%)
Lat 95.00th-qrtle-1 53.00 ( 0.00%) 45.00 ( 15.09%)
Lat 99.00th-qrtle-1 59.00 ( 0.00%) 58.00 ( 1.69%)
Lat 99.50th-qrtle-1 60.00 ( 0.00%) 59.00 ( 1.67%)
Lat 99.90th-qrtle-1 86.00 ( 0.00%) 61.00 ( 29.07%)
Lat 50.00th-qrtle-2 52.00 ( 0.00%) 41.00 ( 21.15%)
Lat 75.00th-qrtle-2 57.00 ( 0.00%) 46.00 ( 19.30%)
Lat 90.00th-qrtle-2 60.00 ( 0.00%) 53.00 ( 11.67%)
Lat 95.00th-qrtle-2 62.00 ( 0.00%) 57.00 ( 8.06%)
Lat 99.00th-qrtle-2 73.00 ( 0.00%) 68.00 ( 6.85%)
Lat 99.50th-qrtle-2 74.00 ( 0.00%) 71.00 ( 4.05%)
Lat 99.90th-qrtle-2 90.00 ( 0.00%) 75.00 ( 16.67%)
Lat 50.00th-qrtle-4 57.00 ( 0.00%) 52.00 ( 8.77%)
Lat 75.00th-qrtle-4 60.00 ( 0.00%) 58.00 ( 3.33%)
Lat 90.00th-qrtle-4 62.00 ( 0.00%) 62.00 ( 0.00%)
Lat 95.00th-qrtle-4 65.00 ( 0.00%) 65.00 ( 0.00%)
Lat 99.00th-qrtle-4 76.00 ( 0.00%) 75.00 ( 1.32%)
Lat 99.50th-qrtle-4 77.00 ( 0.00%) 77.00 ( 0.00%)
Lat 99.90th-qrtle-4 87.00 ( 0.00%) 81.00 ( 6.90%)
Lat 50.00th-qrtle-8 59.00 ( 0.00%) 57.00 ( 3.39%)
Lat 75.00th-qrtle-8 63.00 ( 0.00%) 62.00 ( 1.59%)
Lat 90.00th-qrtle-8 66.00 ( 0.00%) 67.00 ( -1.52%)
Lat 95.00th-qrtle-8 68.00 ( 0.00%) 70.00 ( -2.94%)
Lat 99.00th-qrtle-8 79.00 ( 0.00%) 80.00 ( -1.27%)
Lat 99.50th-qrtle-8 80.00 ( 0.00%) 84.00 ( -5.00%)
Lat 99.90th-qrtle-8 84.00 ( 0.00%) 90.00 ( -7.14%)
Lat 50.00th-qrtle-16 65.00 ( 0.00%) 65.00 ( 0.00%)
Lat 75.00th-qrtle-16 77.00 ( 0.00%) 75.00 ( 2.60%)
Lat 90.00th-qrtle-16 84.00 ( 0.00%) 83.00 ( 1.19%)
Lat 95.00th-qrtle-16 88.00 ( 0.00%) 87.00 ( 1.14%)
Lat 99.00th-qrtle-16 97.00 ( 0.00%) 96.00 ( 1.03%)
Lat 99.50th-qrtle-16 100.00 ( 0.00%) 104.00 ( -4.00%)
Lat 99.90th-qrtle-16 110.00 ( 0.00%) 126.00 ( -14.55%)
Lat 50.00th-qrtle-32 70.00 ( 0.00%) 71.00 ( -1.43%)
Lat 75.00th-qrtle-32 92.00 ( 0.00%) 94.00 ( -2.17%)
Lat 90.00th-qrtle-32 110.00 ( 0.00%) 110.00 ( 0.00%)
Lat 95.00th-qrtle-32 121.00 ( 0.00%) 118.00 ( 2.48%)
Lat 99.00th-qrtle-32 135.00 ( 0.00%) 137.00 ( -1.48%)
Lat 99.50th-qrtle-32 140.00 ( 0.00%) 146.00 ( -4.29%)
Lat 99.90th-qrtle-32 150.00 ( 0.00%) 160.00 ( -6.67%)
Lat 50.00th-qrtle-39 80.00 ( 0.00%) 71.00 ( 11.25%)
Lat 75.00th-qrtle-39 102.00 ( 0.00%) 91.00 ( 10.78%)
Lat 90.00th-qrtle-39 118.00 ( 0.00%) 108.00 ( 8.47%)
Lat 95.00th-qrtle-39 128.00 ( 0.00%) 117.00 ( 8.59%)
Lat 99.00th-qrtle-39 149.00 ( 0.00%) 133.00 ( 10.74%)
Lat 99.50th-qrtle-39 160.00 ( 0.00%) 139.00 ( 13.12%)
Lat 99.90th-qrtle-39 13808.00 ( 0.00%) 4920.00 ( 64.37%)
Despite being nearly identical, it showed a variety of major gains so
I'm not convinced that heavy emphasis should be placed on this particular
workload in terms of evaluating this particular patch. Further evidence of
this is the fact that testing on a UMA machine showed small gains/losses
even though the patch should be a no-op on UMA.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171219085947.13136-2-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
Joel Fernandes
|
9783be2c0e |
sched/fair: Correct obsolete comment about cpufreq_update_util()
Since the remote cpufreq callback work, the cpufreq_update_util() call can happen from remote CPUs. The comment about local CPUs is thus obsolete. Update it accordingly. Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: Android Kernel <kernel-team@android.com> Cc: Atish Patra <atish.patra@oracle.com> Cc: Chris Redpath <Chris.Redpath@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: EAS Dev <eas-dev@lists.linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Ramussen <morten.rasmussen@arm.com> Cc: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Rohit Jain <rohit.k.jain@oracle.com> Cc: Saravana Kannan <skannan@quicinc.com> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vikram Mulukutla <markivx@codeaurora.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/20171215153944.220146-2-joelaf@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Joel Fernandes
|
18cec7e0dd |
sched/fair: Remove impossible condition from find_idlest_group_cpu()
find_idlest_group_cpu() goes through CPUs of a group previous selected by find_idlest_group(). find_idlest_group() returns NULL if the local group is the selected one and doesn't execute find_idlest_group_cpu if the group to which 'cpu' belongs to is chosen. So we're always guaranteed to call find_idlest_group_cpu() with a group to which 'cpu' is non-local. This makes one of the conditions in find_idlest_group_cpu() an impossible one, which we can get rid off. Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Brendan Jackman <brendan.jackman@arm.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Android Kernel <kernel-team@android.com> Cc: Atish Patra <atish.patra@oracle.com> Cc: Chris Redpath <Chris.Redpath@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: EAS Dev <eas-dev@lists.linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Ramussen <morten.rasmussen@arm.com> Cc: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Rohit Jain <rohit.k.jain@oracle.com> Cc: Saravana Kannan <skannan@quicinc.com> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vikram Mulukutla <markivx@codeaurora.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/20171215153944.220146-3-joelaf@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Joel Fernandes
|
f453ae2200 |
sched/fair: Consider RT/IRQ pressure in capacity_spare_wake()
capacity_spare_wake() in the slow path influences choice of idlest groups, as we search for groups with maximum spare capacity. In scenarios where RT pressure is high, a sub optimal group can be chosen and hurt performance of the task being woken up. Fix this by using capacity_of() instead of capacity_orig_of() in capacity_spare_wake(). Tests results from improvements with this change are below. More tests were also done by myself and Matt Fleming to ensure no degradation in different benchmarks. 1) Rohit ran barrier.c test (details below) with following improvements: ------------------------------------------------------------------------ This was Rohit's original use case for a patch he posted at [1] however from his recent tests he showed my patch can replace his slow path changes [1] and there's no need to selectively scan/skip CPUs in find_idlest_group_cpu in the slow path to get the improvement he sees. barrier.c (open_mp code) as a micro-benchmark. It does a number of iterations and barrier sync at the end of each for loop. Here barrier,c is running in along with ping on CPU 0 and 1 as: 'ping -l 10000 -q -s 10 -f hostX' barrier.c can be found at: http://www.spinics.net/lists/kernel/msg2506955.html Following are the results for the iterations per second with this micro-benchmark (higher is better), on a 44 core, 2 socket 88 Threads Intel x86 machine: +--------+------------------+---------------------------+ |Threads | Without patch | With patch | | | | | +--------+--------+---------+-----------------+---------+ | | Mean | Std Dev | Mean | Std Dev | +--------+--------+---------+-----------------+---------+ |1 | 539.36 | 60.16 | 572.54 (+6.15%) | 40.95 | |2 | 481.01 | 19.32 | 530.64 (+10.32%)| 56.16 | |4 | 474.78 | 22.28 | 479.46 (+0.99%) | 18.89 | |8 | 450.06 | 24.91 | 447.82 (-0.50%) | 12.36 | |16 | 436.99 | 22.57 | 441.88 (+1.12%) | 7.39 | |32 | 388.28 | 55.59 | 429.4 (+10.59%)| 31.14 | |64 | 314.62 | 6.33 | 311.81 (-0.89%) | 11.99 | +--------+--------+---------+-----------------+---------+ 2) ping+hackbench test on bare-metal sever (by Rohit) ----------------------------------------------------- Here hackbench is running in threaded mode along with, running ping on CPU 0 and 1 as: 'ping -l 10000 -q -s 10 -f hostX' This test is running on 2 socket, 20 core and 40 threads Intel x86 machine: Number of loops is 10000 and runtime is in seconds (Lower is better). +--------------+-----------------+--------------------------+ |Task Groups | Without patch | With patch | | +-------+---------+----------------+---------+ |(Groups of 40)| Mean | Std Dev | Mean | Std Dev | +--------------+-------+---------+----------------+---------+ |1 | 0.851 | 0.007 | 0.828 (+2.77%)| 0.032 | |2 | 1.083 | 0.203 | 1.087 (-0.37%)| 0.246 | |4 | 1.601 | 0.051 | 1.611 (-0.62%)| 0.055 | |8 | 2.837 | 0.060 | 2.827 (+0.35%)| 0.031 | |16 | 5.139 | 0.133 | 5.107 (+0.63%)| 0.085 | |25 | 7.569 | 0.142 | 7.503 (+0.88%)| 0.143 | +--------------+-------+---------+----------------+---------+ [1] https://patchwork.kernel.org/patch/9991635/ Matt Fleming also ran several different hackbench tests and cyclic test to santiy-check that the patch doesn't harm other usecases. Tested-by: Matt Fleming <matt@codeblueprint.co.uk> Tested-by: Rohit Jain <rohit.k.jain@oracle.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Atish Patra <atish.patra@oracle.com> Cc: Brendan Jackman <brendan.jackman@arm.com> Cc: Chris Redpath <Chris.Redpath@arm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Ramussen <morten.rasmussen@arm.com> Cc: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Saravana Kannan <skannan@quicinc.com> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vikram Mulukutla <markivx@codeaurora.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/20171214212158.188190-1-joelaf@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
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f01415fdbf |
sched/fair: Use 'unsigned long' for utilization, consistently
Utilization and capacity are tracked as 'unsigned long', however some functions using them return an 'int' which is ultimately assigned back to 'unsigned long' variables. Since there is not scope on using a different and signed type, consolidate the signature of functions returning utilization to always use the native type. This change improves code consistency, and it also benefits code paths where utilizations should be clamped by avoiding further type conversions or ugly type casts. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Chris Redpath <chris.redpath@arm.com> Reviewed-by: Brendan Jackman <brendan.jackman@arm.com> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@android.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/20171205171018.9203-2-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Cheng Jian
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a555e9d86e |
sched/fair: Remove unused 'curr' parameter from wakeup_gran
The first parameter of wakeup_gran(), 'curr', is unnecessary now. Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: huawei.libin@huawei.com Cc: xiexiuqi@huawei.com Link: http://lkml.kernel.org/r/1512653443-179848-1-git-send-email-cj.chengjian@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vincent Guittot
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a4c3c04974 |
sched/fair: Update and fix the runnable propagation rule
Unlike running, the runnable part can't be directly propagated through the hierarchy when we migrate a task. The main reason is that runnable time can be shared with other sched_entities that stay on the rq and this runnable time will also remain on prev cfs_rq and must not be removed. Instead, we can estimate what should be the new runnable of the prev cfs_rq and check that this estimation stay in a possible range. The prop_runnable_sum is a good estimation when adding runnable_sum but fails most often when we remove it. Instead, we could use the formula below instead: gcfs_rq's runnable_sum = gcfs_rq->avg.load_sum / gcfs_rq->load.weight which assumes that tasks are equally runnable which is not true but easy to compute. Beside these estimates, we have several simple rules that help us to filter out wrong ones: - ge->avg.runnable_sum <= than LOAD_AVG_MAX - ge->avg.runnable_sum >= ge->avg.running_sum (ge->avg.util_sum << LOAD_AVG_MAX) - ge->avg.runnable_sum can't increase when we detach a task The effect of these fixes is better cgroups balancing. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ben Segall <bsegall@google.com> Cc: Chris Mason <clm@fb.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yuyang Du <yuyang.du@intel.com> Link: http://lkml.kernel.org/r/1510842112-21028-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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22714a2ba4 |
Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
"Cgroup2 cpu controller support is finally merged.
- Basic cpu statistics support to allow monitoring by default without
the CPU controller enabled.
- cgroup2 cpu controller support.
- /sys/kernel/cgroup files to help dealing with new / optional
features"
* 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: export list of cgroups v2 features using sysfs
cgroup: export list of delegatable control files using sysfs
cgroup: mark @cgrp __maybe_unused in cpu_stat_show()
MAINTAINERS: relocate cpuset.c
cgroup, sched: Move basic cpu stats from cgroup.stat to cpu.stat
sched: Implement interface for cgroup unified hierarchy
sched: Misc preps for cgroup unified hierarchy interface
sched/cputime: Add dummy cputime_adjust() implementation for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
cgroup: statically initialize init_css_set->dfl_cgrp
cgroup: Implement cgroup2 basic CPU usage accounting
cpuacct: Introduce cgroup_account_cputime[_field]()
sched/cputime: Expose cputime_adjust()
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Ingo Molnar
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8a103df440 |
Merge branch 'linus' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Greg Kroah-Hartman
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b24413180f |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Frederic Weisbecker
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de201559df |
sched/isolation: Introduce housekeeping flags
Before we implement isolcpus under housekeeping, we need the isolation features to be more finegrained. For example some people want NOHZ_FULL without the full scheduler isolation, others want full scheduler isolation without NOHZ_FULL. So let's cut all these isolation features piecewise, at the risk of overcutting it right now. We can still merge some flags later if they always make sense together. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1509072159-31808-9-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Frederic Weisbecker
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204c083a00 |
sched/isolation: Rename is_housekeeping_cpu() to housekeeping_cpu()
Fit it into the housekeeping_*() namespace. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1509072159-31808-7-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |