Later changes will add reference count checking for struct map, add a
helper function to invoke the map_ip and unmap_ip function pointers. The
helper allows the reference count check to be in fewer places.
Committer notes:
Add missing conversions to:
tools/perf/util/map.c
tools/perf/util/cs-etm.c
tools/perf/util/annotate.c
tools/perf/arch/powerpc/util/sym-handling.c
tools/perf/arch/s390/annotate/instructions.c
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It needs callstacks for two reasons:
* for stack aggregation mode, the map key is the stack id and it can
also show the full stack traces when -v is used
* for other aggregation modes, the stack filter can be used to limit
lock contentions from known call paths
The -v option is meaningful (in terms of stack trace) only for stack
aggregation mode, so it should not set the save_callstack for other
mode like with -t or -l options.
I've noticed this with the following command line:
$ sudo ./perf lock con -ablv -E 3 -M 16 -- ./perf bench sched messaging
...
contended total wait max wait avg wait address symbol
88 4.59 ms 108.07 us 52.13 us ffff935757f46ec0 (spinlock)
33 905.22 us 73.67 us 27.43 us ffff935757f41700 (spinlock)
28 703.69 us 79.28 us 25.13 us ffff938a3d9b0c80 rq_lock (spinlock)
=== output for debug ===
bad: 12272, total: 12421
bad rate: 98.80 %
histogram of failure reasons
task: 8285
stack: 3987 <---------- here
time: 0
data: 0
It should not have any failure on stacks since it doesn't use it.
No functional change intended.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230406210611.1622492-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When -E option is used, it only prints the given number of entries but
the event stat at the end should have the numbers for entire entries.
Likewise, -S option will hide entries that don't have the named
function in the callstack. Also update event stat for them.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230406210611.1622492-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It's possible to fail to update the data when the lock_stat map is full.
We should check that case and show the number at the end.
$ sudo ./perf lock con -ablv -E3 -- ./perf bench sched messaging
...
contended total wait max wait avg wait address symbol
6157 208.48 ms 69.29 us 33.86 us ffff934c001c1f00 (spinlock)
4030 72.04 ms 61.84 us 17.88 us ffff934c000415c0 (spinlock)
3201 50.30 ms 47.73 us 15.71 us ffff934c2eead850 (spinlock)
=== output for debug ===
bad: 0, total: 13388
bad rate: 0.00 %
histogram of failure reasons
task: 0
stack: 0
time: 0
data: 0 <----- added
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230406210611.1622492-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
struct map is reference counted, having it also be a node in an
red-black tree complicates the reference counting. Switch to having a
map_rb_node which is a red-block tree node but points at the reference
counted struct map. This reference is responsible for a single reference
count.
Committer notes:
Fixed up tools/perf/util/unwind-libunwind-local.c to use map_rb_node as
well.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It can fail to collect lock stat from BPF for various reasons. For
example, I've got a report that sometimes time calculation seems wrong
in case of contended spinlocks. I suspect the time delta went negative
for some reason.
Count them separately and show in the output like below:
$ sudo perf lock contention -abE5 sleep 10
contended total wait max wait avg wait type caller
13 785.61 us 79.36 us 60.43 us spinlock remove_wait_queue+0x14
10 469.02 us 87.51 us 46.90 us spinlock prepare_to_wait+0x27
9 289.09 us 69.08 us 32.12 us spinlock finish_wait+0x36
114 251.05 us 8.56 us 2.20 us spinlock try_to_wake_up+0x1f5
132 188.63 us 5.01 us 1.43 us spinlock __wake_up_common_lock+0x62
=== output for debug ===
bad: 1, total: 279
bad rate: 0.36 %
histogram of failure reasons
task: 1
stack: 0
time: 0
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230327225711.245738-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I got a report of a msan failure like below:
$ sudo perf lock con -ab -- sleep 1
...
==224416==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x5651160d6c96 in lock_contention_read util/bpf_lock_contention.c:290:8
#1 0x565115f90870 in __cmd_contention builtin-lock.c:1919:3
#2 0x565115f90870 in cmd_lock builtin-lock.c:2385:8
#3 0x565115f03a83 in run_builtin perf.c:330:11
#4 0x565115f03756 in handle_internal_command perf.c:384:8
#5 0x565115f02d53 in run_argv perf.c:428:2
#6 0x565115f02d53 in main perf.c:562:3
#7 0x7f43553bc632 in __libc_start_main
#8 0x565115e865a9 in _start
It was because the 'key' variable is not initialized. Actually it'd be set
by bpf_map_get_next_key() but msan didn't seem to understand it. Let's make
msan happy by initializing the variable.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230324001922.937634-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Using the BPF_PROG_RUN mechanism, we can run a raw_tp BPF program to
collect some semi-global locks like per-cpu locks. Let's add runqueue
locks using bpf_per_cpu_ptr() helper.
$ sudo ./perf lock con -abl -- sleep 1
contended total wait max wait avg wait address symbol
248 3.25 ms 32.23 us 13.10 us ffff8cc75cfd2940 siglock
60 217.91 us 9.69 us 3.63 us ffff8cc700061c00
8 70.23 us 13.86 us 8.78 us ffff8cc703629484
4 56.32 us 35.81 us 14.08 us ffff8cc78b66f778 mmap_lock
4 16.70 us 5.18 us 4.18 us ffff8cc7036a0684
3 4.99 us 2.65 us 1.66 us ffff8d053da30c80 rq_lock
2 3.44 us 2.28 us 1.72 us ffff8d053dcf0c80 rq_lock
9 2.51 us 371 ns 278 ns ffff8ccb92479440
2 2.11 us 1.24 us 1.06 us ffff8d053db30c80 rq_lock
2 2.06 us 1.69 us 1.03 us ffff8d053d970c80 rq_lock
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230313204825.2665483-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Likewise, we can display siglock by following the pointer like
current->sighand->siglock.
$ sudo ./perf lock con -abl -- sleep 1
contended total wait max wait avg wait address symbol
16 2.18 ms 305.35 us 136.34 us ffffffff92e06080 tasklist_lock
28 521.78 us 31.16 us 18.63 us ffff8cc703783ec4
7 119.03 us 23.55 us 17.00 us ffff8ccb92479440
15 88.29 us 10.06 us 5.89 us ffff8cd560b5f380 siglock
7 37.67 us 9.16 us 5.38 us ffff8d053daf0c80
5 8.81 us 4.92 us 1.76 us ffff8d053d6b0c80
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230313204825.2665483-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When there're many lock contentions in the system, people sometimes want
to know who caused the contention, IOW who's the owner of the locks.
The -o/--lock-owner option tries to follow the lock owners for the
contended mutexes and rwsems from BPF, and then attributes the
contention time to the owner instead of the waiter. It's a best effort
approach to get the owner info at the time of the contention and doesn't
guarantee to have the precise tracking of owners if it's changing over
time.
Currently it only handles mutex and rwsem that have owner field in their
struct and it basically points to a task_struct that owns the lock at
the moment.
Technically its type is atomic_long_t and it comes with some LSB bits
used for other meanings. So it needs to clear them when casting it to a
pointer to task_struct.
Also the atomic_long_t is a typedef of the atomic 32 or 64 bit types
depending on arch which is a wrapper struct for the counter value. I'm
not aware of proper ways to access those kernel atomic types from BPF so
I just read the internal counter value directly. Please let me know if
there's a better way.
When -o/--lock-owner option is used, it goes to the task aggregation
mode like -t/--threads option does. However it cannot get the owner for
other lock types like spinlock and sometimes even for mutex.
$ sudo ./perf lock con -abo -- ./perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
Total time: 4.766 [sec]
4.766540 usecs/op
209795 ops/sec
contended total wait max wait avg wait pid owner
403 565.32 us 26.81 us 1.40 us -1 Unknown
4 27.99 us 8.57 us 7.00 us 1583145 sched-pipe
1 8.25 us 8.25 us 8.25 us 1583144 sched-pipe
1 2.03 us 2.03 us 2.03 us 5068 chrome
As you can see, the owner is unknown for the most cases. But if we
filter only for the mutex locks, it'd more likely get the onwers.
$ sudo ./perf lock con -abo -Y mutex -- ./perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
Total time: 4.910 [sec]
4.910435 usecs/op
203647 ops/sec
contended total wait max wait avg wait pid owner
2 15.50 us 8.29 us 7.75 us 1582852 sched-pipe
7 7.20 us 2.47 us 1.03 us -1 Unknown
1 6.74 us 6.74 us 6.74 us 1582851 sched-pipe
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230207002403.63590-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It'd be useful to filter other than the current aggregation mode. For
example, users may want to see callstacks for specific locks only. Or
they may want tasks from a certain callstack.
The tracepoints already collected the information but it needs to check
the condition again when processing the event. And it needs to change
BPF to allow the key combinations.
The lock contentions on 'rcu_state' spinlock can be monitored:
$ sudo perf lock con -abv -L rcu_state sleep 1
...
contended total wait max wait avg wait type caller
4 151.39 us 62.57 us 37.85 us spinlock rcu_core+0xcb
0xffffffff81fd1666 _raw_spin_lock_irqsave+0x46
0xffffffff8172d76b rcu_core+0xcb
0xffffffff822000eb __softirqentry_text_start+0xeb
0xffffffff816a0ba9 __irq_exit_rcu+0xc9
0xffffffff81fc0112 sysvec_apic_timer_interrupt+0xa2
0xffffffff82000e46 asm_sysvec_apic_timer_interrupt+0x16
0xffffffff81d49f78 cpuidle_enter_state+0xd8
0xffffffff81d4a259 cpuidle_enter+0x29
1 30.21 us 30.21 us 30.21 us spinlock rcu_core+0xcb
0xffffffff81fd1666 _raw_spin_lock_irqsave+0x46
0xffffffff8172d76b rcu_core+0xcb
0xffffffff822000eb __softirqentry_text_start+0xeb
0xffffffff816a0ba9 __irq_exit_rcu+0xc9
0xffffffff81fc00c4 sysvec_apic_timer_interrupt+0x54
0xffffffff82000e46 asm_sysvec_apic_timer_interrupt+0x16
1 28.84 us 28.84 us 28.84 us spinlock rcu_accelerate_cbs_unlocked+0x40
0xffffffff81fd1c60 _raw_spin_lock+0x30
0xffffffff81728cf0 rcu_accelerate_cbs_unlocked+0x40
0xffffffff8172da82 rcu_core+0x3e2
0xffffffff822000eb __softirqentry_text_start+0xeb
0xffffffff816a0ba9 __irq_exit_rcu+0xc9
0xffffffff81fc0112 sysvec_apic_timer_interrupt+0xa2
0xffffffff82000e46 asm_sysvec_apic_timer_interrupt+0x16
0xffffffff81d49f78 cpuidle_enter_state+0xd8
...
To see tasks calling 'rcu_core' function:
$ sudo perf lock con -abt -S rcu_core sleep 1
contended total wait max wait avg wait pid comm
19 23.46 us 2.21 us 1.23 us 0 swapper
2 18.37 us 17.01 us 9.19 us 2061859 ThreadPoolForeg
3 5.76 us 1.97 us 1.92 us 3909 pipewire-pulse
1 2.26 us 2.26 us 2.26 us 1809271 MediaSu~isor #2
1 1.97 us 1.97 us 1.97 us 1514882 Chrome_ChildIOT
1 987 ns 987 ns 987 ns 3740 pipewire-pulse
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230203021324.143540-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This is a preparation work to support complex keys of BPF maps. Now it
has single value key according to the aggregation mode like stack_id or
pid. But we want to use a combination of those keys.
Then lock_contention_read() should still aggregate the result based on
the key that was requested by user. The other key info will be used for
filtering.
So instead of creating a lock_stat entry always, Check if it's already
there using lock_stat_find() first.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230203021324.143540-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The lock_contention_get_name() returns a name for the lock stat entry
based on the current aggregation mode. As it's called sequentially in a
single thread, it can return the address of a static buffer for symbol
and offset of the caller.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230203021324.143540-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The -S/--callstack-filter is to limit display entries having the given
string in the callstack (not only in the caller in the output).
The following example shows lock contention results if the callstack
has 'net' substring somewhere. Note that the caller '__dev_queue_xmit'
does not match to it, but it has 'inet6_csk_xmit' in the callstack.
This applies even if you don't use -v option to show the full callstack.
$ sudo ./perf lock con -abv -S net sleep 1
...
contended total wait max wait avg wait type caller
5 70.20 us 16.13 us 14.04 us spinlock __dev_queue_xmit+0xb6d
0xffffffffa5dd1c60 _raw_spin_lock+0x30
0xffffffffa5b8f6ed __dev_queue_xmit+0xb6d
0xffffffffa5cd8267 ip6_finish_output2+0x2c7
0xffffffffa5cdac14 ip6_finish_output+0x1d4
0xffffffffa5cdb477 ip6_xmit+0x457
0xffffffffa5d1fd17 inet6_csk_xmit+0xd7
0xffffffffa5c5f4aa __tcp_transmit_skb+0x54a
0xffffffffa5c6467d tcp_keepalive_timer+0x2fd
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230126000936.3017683-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Likewise, add addr_filter BPF hash map and check it with the lock
address.
$ sudo ./perf lock con -ab -L tasklist_lock -- ./perf bench sched messaging
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run
Total time: 0.169 [sec]
contended total wait max wait avg wait type caller
18 174.09 us 25.31 us 9.67 us rwlock:W do_exit+0x36d
5 32.34 us 10.87 us 6.47 us rwlock:R do_wait+0x8b
4 15.41 us 4.73 us 3.85 us rwlock:W release_task+0x6e
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221219201732.460111-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Likewise, add type_filter BPF hash map and check it when user gave a
lock type filter.
$ sudo ./perf lock con -ab -Y rwlock -- ./perf bench sched messaging
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run
Total time: 0.203 [sec]
contended total wait max wait avg wait type caller
15 156.19 us 19.45 us 10.41 us rwlock:W do_exit+0x36d
1 11.12 us 11.12 us 11.12 us rwlock:R do_wait+0x8b
1 5.09 us 5.09 us 5.09 us rwlock:W release_task+0x6e
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221219201732.460111-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The data type of the verbose variable is integer and can be negative,
replace improperly used cases in a unified manner:
1. if (verbose) => if (verbose > 0)
2. if (!verbose) => if (verbose <= 0)
3. if (XX && verbose) => if (XX && verbose > 0)
4. if (XX && !verbose) => if (XX && verbose <= 0)
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20221220035702.188413-3-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The -l/--lock-addr option is to implement per-lock-instance contention
stat using LOCK_AGGR_ADDR. It displays lock address and optionally
symbol name if exists.
$ sudo ./perf lock con -abl sleep 1
contended total wait max wait avg wait address symbol
1 36.28 us 36.28 us 36.28 us ffff92615d6448b8
9 10.91 us 1.84 us 1.21 us ffffffffbaed50c0 rcu_state
1 10.49 us 10.49 us 10.49 us ffff9262ac4f0c80
8 4.68 us 1.67 us 585 ns ffffffffbae07a40 jiffies_lock
3 3.03 us 1.45 us 1.01 us ffff9262277861e0
1 924 ns 924 ns 924 ns ffff926095ba9d20
1 436 ns 436 ns 436 ns ffff9260bfda4f60
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221209190727.759804-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The BPF didn't show the per-thread stat properly. Use task's thread id (PID)
as a key instead of stack_id and add a task_data map to save task comm names.
$ sudo ./perf lock con -abt -E 5 sleep 1
contended total wait max wait avg wait pid comm
1 740.66 ms 740.66 ms 740.66 ms 1950 nv_queue
3 305.50 ms 298.19 ms 101.83 ms 1884 nvidia-modeset/
1 25.14 us 25.14 us 25.14 us 2725038 EventManager_De
12 23.09 us 9.30 us 1.92 us 0 swapper
1 20.18 us 20.18 us 20.18 us 2725033 EventManager_De
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221209190727.759804-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Accessing BPF maps should use the same data types. Add bpf_skel/lock_data.h
to define the common data structures. No functional changes.
Committer notes:
Fixed contention_key.stack_id missing rename to contention_key.stack_or_task_id.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221209190727.759804-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It is used in bpf_lock_contention.c and builtin-lock.c will be made
CONFIG_LIBTRACEEVENT=y conditional, so move it to machine.c, that is
always available.
This makes those 4 global variables for sched and lock text start and
end to move to 'struct machine' too, as conceivably we can have that
info for several machine instances, say some 'perf diff' like tool.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It caused some troubles when a lock inside kmalloc is contended
because task local storage would allocate memory using kmalloc.
It'd create a recusion and even crash in my system.
There could be a couple of workarounds but I think the simplest
one is to use a pre-allocated hash map. We could fix the task
local storage to use the safe BPF allocator, but it takes time
so let's change this until it happens actually.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Chris Li <chriscli@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221118190109.1512674-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The msan also warns about the use of VLA for stack_trace variable.
We can dynamically allocate instead. While at it, simplify the error
handle a bit (and fix bugs).
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221028180128.3311491-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The msan reported a use-of-uninitialized-value warning for the struct
lock_contention_data in lock_contention_read(). While it'd be filled
by bpf_map_lookup_elem(), let's just initialize it to silence the
warning.
==12524==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x562b0f16b1cd in lock_contention_read util/bpf_lock_contention.c:139:7
#1 0x562b0ef65ec6 in __cmd_contention builtin-lock.c:1737:3
#2 0x562b0ef65ec6 in cmd_lock builtin-lock.c:1992:8
#3 0x562b0ee7f50b in run_builtin perf.c:322:11
#4 0x562b0ee7efc1 in handle_internal_command perf.c:376:8
#5 0x562b0ee7e1e9 in run_argv perf.c:420:2
#6 0x562b0ee7e1e9 in main perf.c:550:3
#7 0x7f065f10e632 in __libc_start_main (/usr/lib64/libc.so.6+0x61632)
#8 0x562b0edf2fa9 in _start (perf+0xfa9)
SUMMARY: MemorySanitizer: use-of-uninitialized-value (perf+0xe15160) in lock_contention_read
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221028180128.3311491-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The struct lock_contention_key is never used, remove it.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/linux-perf-users/20220927013931.110475-6-yuancan@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently it collects stack traces to max size then skip entries.
Because we don't have control how to skip perf callchains. But BPF can
do it with bpf_get_stackid() with a flag.
Say we have max-stack=4 and stack-skip=2, we get these stack traces.
Before: After:
.---> +---+ <--. .---> +---+ <--.
| | | | | | | |
| +---+ usable | +---+ |
max | | | max | | |
stack +---+ <--' stack +---+ usable
| | X | | | | |
| +---+ skip | +---+ |
| | X | | | | |
`---> +---+ `---> +---+ <--' <=== collection
| X |
+---+ skip
| X |
+---+
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220912055314.744552-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It needs stack traces to find callers of locks. To minimize the
performance overhead it only collects up to 8 entries for each stack
trace. And it skips first 3 entries as they came from BPF, tracepoint
and lock functions which are not interested for most users.
But it turned out that those numbers are different in some
configuration. Using fixed number can result in non meaningful caller
names. Let's make them adjustable with --stack-depth and --skip-stack
options.
On my setup, the default output is like below:
# /perf lock con -ab -F contended,wait_total sleep 3
contended total wait type caller
28 4.55 ms rwlock:W __bpf_trace_contention_begin+0xb
33 1.67 ms rwlock:W __bpf_trace_contention_begin+0xb
12 580.28 us spinlock __bpf_trace_contention_begin+0xb
60 240.54 us rwsem:R __bpf_trace_contention_begin+0xb
27 64.45 us spinlock __bpf_trace_contention_begin+0xb
If I change the stack skip to 5, the result will be like:
# perf lock con -ab -F contended,wait_total --stack-skip 5 sleep 3
contended total wait type caller
32 715.45 us spinlock folio_lruvec_lock_irqsave+0x61
26 550.22 us spinlock folio_lruvec_lock_irqsave+0x61
15 486.93 us rwsem:R mmap_read_lock+0x13
12 139.66 us rwsem:W vm_mmap_pgoff+0x93
1 7.04 us spinlock tick_do_update_jiffies64+0x25
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220912055314.744552-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently it shows a caller function for each entry, but users need to see
the full call stacks sometimes. Use -v/--verbose option to do that.
# perf lock con -a -b -v sleep 3
Looking at the vmlinux_path (8 entries long)
symsrc__init: cannot get elf header.
Using /proc/kcore for kernel data
Using /proc/kallsyms for symbols
contended total wait max wait avg wait type caller
1 10.74 us 10.74 us 10.74 us spinlock __bpf_trace_contention_begin+0xb
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffbb8b8e75 bpf_trace_run2+0x35
0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb
0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5
0xffffffffbc1c26ff _raw_spin_lock+0x1f
0xffffffffbb841015 tick_do_update_jiffies64+0x25
0xffffffffbb8409ee tick_irq_enter+0x9e
1 7.70 us 7.70 us 7.70 us spinlock __bpf_trace_contention_begin+0xb
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117
0xffffffffbb8b8e75 bpf_trace_run2+0x35
0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb
0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5
0xffffffffbc1c26ff _raw_spin_lock+0x1f
0xffffffffbb7bc27e raw_spin_rq_lock_nested+0xe
0xffffffffbb7cef9c load_balance+0x66c
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220912055314.744552-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Like the normal 'perf lock contention' output, it'd print the number of
lost entries for BPF if exists or -v option is passed.
Currently it uses BROKEN_CONTENDED stat for the lost count (due to full
stack maps).
$ sudo perf lock con -a -b --map-nr-entries 128 sleep 5
...
=== output for debug===
bad: 43, total: 14903
bad rate: 0.29 %
histogram of events caused bad sequence
acquire: 0
acquired: 0
contended: 43
release: 0
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220802191004.347740-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The --map-nr-entries option is to control number of max entries in the
perf lock contention BPF maps.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220802191004.347740-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The lock_contention struct is to carry related fields together and to
minimize the change when we add new config options.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220802191004.347740-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add -a/--all-cpus and -C/--cpu options for cpu filtering. Also -p/--pid
and --tid options are added for task filtering. The short -t option is
taken for --threads already. Tracking the command line workload is
possible as well.
$ sudo perf lock contention -a -b sleep 1
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220729200756.666106-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add -b/--use-bpf option to use BPF to collect lock contention stats.
For simplicity it now runs system-wide and requires C-c to stop.
Upcoming changes will add the usual filtering.
$ sudo perf lock con -b
^C
contended total wait max wait avg wait type caller
42 192.67 us 13.64 us 4.59 us spinlock queue_work_on+0x20
23 85.54 us 10.28 us 3.72 us spinlock worker_thread+0x14a
6 13.92 us 6.51 us 2.32 us mutex kernfs_iop_permission+0x30
3 11.59 us 10.04 us 3.86 us mutex kernfs_dop_revalidate+0x3c
1 7.52 us 7.52 us 7.52 us spinlock kthread+0x115
1 7.24 us 7.24 us 7.24 us rwlock:W sys_epoll_wait+0x148
2 7.08 us 3.99 us 3.54 us spinlock delayed_work_timer_fn+0x1b
1 6.41 us 6.41 us 6.41 us spinlock idle_balance+0xa06
2 2.50 us 1.83 us 1.25 us mutex kernfs_iop_lookup+0x2f
1 1.71 us 1.71 us 1.71 us mutex kernfs_iop_getattr+0x2c
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220729200756.666106-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
