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797 Commits

Author SHA1 Message Date
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
  ...
 2018-10-23 15:00:03 +01:00
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:

  b60205c7c5 ("sched/fair: Fix min_vruntime tracking")

I think that we want to update min_vruntime when a task is sleeping/migrating.
So, the check is inverted there - fix it.

Signed-off-by: Song Muchun <smuchun@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>
Fixes: b60205c7c5 ("sched/fair: Fix min_vruntime tracking")
Link: http://lkml.kernel.org/r/20181014112612.2614-1-smuchun@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-10-16 09:36:01 +02:00
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
c06f04c704 to put throttled entries at the head of the list, later entries
on the list will starve.  Essentially, the same X processes will get pulled
off the list, given CPU time and then, when expired, get put back on the
head of the list where distribute_cfs_runtime will give runtime to the same
set of processes leaving the rest.

Fix the issue by setting a bit in struct cfs_bandwidth when
distribute_cfs_runtime is running, so that the code in throttle_cfs_rq can
decide to put the throttled entry on the tail or the head of the list.  The
bit is set/cleared by the callers of distribute_cfs_runtime while they hold
cfs_bandwidth->lock.

This is easy to reproduce with a handful of CPU consumers. I use 'crash' on
the live system. In some cases you can simply look at the throttled list and
see the later entries are not changing:

  crash> list cfs_rq.throttled_list -H 0xffff90b54f6ade40 -s cfs_rq.runtime_remaining | paste - - | awk '{print $1"  "$4}' | pr -t -n3
    1     ffff90b56cb2d200  -976050
    2     ffff90b56cb2cc00  -484925
    3     ffff90b56cb2bc00  -658814
    4     ffff90b56cb2ba00  -275365
    5     ffff90b166a45600  -135138
    6     ffff90b56cb2da00  -282505
    7     ffff90b56cb2e000  -148065
    8     ffff90b56cb2fa00  -872591
    9     ffff90b56cb2c000  -84687
   10     ffff90b56cb2f000  -87237
   11     ffff90b166a40a00  -164582

  crash> list cfs_rq.throttled_list -H 0xffff90b54f6ade40 -s cfs_rq.runtime_remaining | paste - - | awk '{print $1"  "$4}' | pr -t -n3
    1     ffff90b56cb2d200  -994147
    2     ffff90b56cb2cc00  -306051
    3     ffff90b56cb2bc00  -961321
    4     ffff90b56cb2ba00  -24490
    5     ffff90b166a45600  -135138
    6     ffff90b56cb2da00  -282505
    7     ffff90b56cb2e000  -148065
    8     ffff90b56cb2fa00  -872591
    9     ffff90b56cb2c000  -84687
   10     ffff90b56cb2f000  -87237
   11     ffff90b166a40a00  -164582

Sometimes it is easier to see by finding a process getting starved and looking
at the sched_info:

  crash> task ffff8eb765994500 sched_info
  PID: 7800   TASK: ffff8eb765994500  CPU: 16  COMMAND: "cputest"
    sched_info = {
      pcount = 8,
      run_delay = 697094208,
      last_arrival = 240260125039,
      last_queued = 240260327513
    },
  crash> task ffff8eb765994500 sched_info
  PID: 7800   TASK: ffff8eb765994500  CPU: 16  COMMAND: "cputest"
    sched_info = {
      pcount = 8,
      run_delay = 697094208,
      last_arrival = 240260125039,
      last_queued = 240260327513
    },

Signed-off-by: Phil Auld <pauld@redhat.com>
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>
Cc: stable@vger.kernel.org
Fixes: c06f04c704 ("sched: Fix potential near-infinite distribute_cfs_runtime() loop")
Link: http://lkml.kernel.org/r/20181008143639.GA4019@pauld.bos.csb
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-10-11 13:10:18 +02:00
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>
 2018-10-02 11:31:33 +02:00
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:

  2e62c4743a ("sched/fair: Remove #ifdefs from scale_rt_capacity()")

Suggested-by: Ingo Molnar <mingo@redhat.com>
Reported-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Reported-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: dou_liyang@163.com
Fixes: 2e62c4743a ("sched/fair: Remove #ifdefs from scale_rt_capacity()")
Link: http://lkml.kernel.org/r/1537867062-27285-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-10-02 09:45:00 +02:00
Ingo Molnar
b429f71bca Merge branch 'sched/urgent' into sched/core, to pick up fixes 
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-10-02 09:43:39 +02:00
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>
 2018-10-02 09:42:28 +02:00
Mel Gorman
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>
 2018-10-02 09:42:24 +02:00
Srikar Dronamraju
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>
 2018-10-02 09:42:23 +02:00
Srikar Dronamraju
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>
 2018-10-02 09:42:21 +02:00
Srikar Dronamraju
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>
 2018-10-02 09:42:20 +02:00
Vincent Guittot
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>
 2018-09-10 11:05:56 +02:00
Vincent Guittot
d90707ebeb sched/numa: Remove unused code from update_numa_stats() 
With:

  commit 2d4056fafa ("sched/numa: Remove numa_has_capacity()")

the local variables 'smt', 'cpus' and 'capacity' and their results are not used
anymore in numa_has_capacity()

Remove this unused code.

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/1535548752-4434-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-09-10 11:05:55 +02:00
Chris Redpath
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>
 2018-09-10 11:05:53 +02:00
Valentin Schneider
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>
 2018-09-10 11:05:53 +02:00
Valentin Schneider
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>
 2018-09-10 11:05:52 +02:00
Valentin Schneider
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>
 2018-09-10 11:05:51 +02:00
Valentin Schneider
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>
 2018-09-10 11:05:51 +02:00
Morten Rasmussen
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>
 2018-09-10 11:05:50 +02:00
Morten Rasmussen
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>
 2018-09-10 11:05:49 +02:00
Morten Rasmussen
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>
 2018-09-10 11:05:49 +02:00
Morten Rasmussen
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>
 2018-09-10 11:05:48 +02:00
Randy Dunlap
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: ea14b57e8a ("sched/cpufreq: Provide migration hint")
Link: http://lkml.kernel.org/r/cdda0d42-880d-4229-a9f7-5899c977a063@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-09-10 10:31:37 +02:00
Vincent Guittot
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>
 2018-09-10 10:13:49 +02:00
Vincent Guittot
287cdaac57 sched/fair: Fix scale_rt_capacity() for SMT 
Since commit:

  523e979d31 ("sched/core: Use PELT for scale_rt_capacity()")

scale_rt_capacity() returns the remaining capacity and not a scale factor
to apply on cpu_capacity_orig. arch_scale_cpu() is directly called by
scale_rt_capacity() so we must take the sched_domain argument.

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 523e979d31 ("sched/core: Use PELT for scale_rt_capacity()")
Link: http://lkml.kernel.org/r/20180904093626.GA23936@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-09-10 10:13:47 +02:00
Steve Muckle
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: b5179ac70d ("sched/fair: Prepare to fix fairness problems on migration")
Link: http://lkml.kernel.org/r/20180831224217.169476-1-smuckle@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-09-10 10:13:47 +02:00
Vincent Guittot
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: 371bf42732 ("sched/rt: Add rt_rq utilization tracking")
Fixes: 3727e0e163 ("sched/dl: Add dl_rq utilization tracking")
Link: http://lkml.kernel.org/r/1535728975-22799-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-09-10 10:13:46 +02:00
Linus Torvalds
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
  ...
 2018-08-14 09:46:06 -07:00
Thomas Gleixner
f2701b77bb Merge 4.18-rc7 into master to pick up the KVM dependcy 
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 2018-08-05 16:39:29 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:08 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:08 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:08 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:08 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:07 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:07 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:07 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:06 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:06 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:06 +02:00
Srikar Dronamraju
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>
 2018-07-25 11:41:06 +02:00
Vincent Guittot
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>
 2018-07-25 11:41:05 +02:00
Vincent Guittot
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>
 2018-07-16 00:16:29 +02:00
Vincent Guittot
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>
 2018-07-16 00:16:25 +02:00
Vincent Guittot
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>
 2018-07-15 23:51:21 +02:00
Vincent Guittot
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>
 2018-07-15 23:51:20 +02:00
Vincent Guittot
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>
 2018-07-15 23:51:20 +02:00
Vincent Guittot
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>
 2018-07-15 23:51:20 +02:00
Quentin Perret
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>
 2018-07-15 23:51:20 +02:00
Ingo Molnar
4520843dfa Merge branch 'sched/urgent' into sched/core, to pick up fixes 
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-07-03 09:20:22 +02:00
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: 7f65ea42eb ("sched/fair: Add util_est on top of PELT")
Link: http://lkml.kernel.org/r/1528972380-16268-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2018-07-03 09:17:30 +02:00