kernel/linux.git/tools/perf/util/kwork.h, branch v6.19.12

perf kwork: Make perf_kwork_add_work a callback

2024-12-18T19:24:33+00:00

perf_kwork_add_work is declared in builtin-kwork, whereas much kwork code is in util. To avoid needing to stub perf_kwork_add_work in python.c, add a callback to struct perf_kwork and initialize it in builtin-kwork to perf_kwork_add_work - this is the only struct perf_kwork. This removes the need for the stub in python.c. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Colin Ian King Cc: Dapeng Mi Cc: Howard Chu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Josh Poimboeuf Cc: Kan Liang Cc: Mark Rutland Cc: Michael Petlan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Richter Cc: Veronika Molnarova Cc: Weilin Wang Link: https://lore.kernel.org/r/20241119011644.971342-18-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf cpumap: Reduce transitive dependencies on libperf MAX_NR_CPUS

2024-12-09T20:52:41+00:00

libperf exposes MAX_NR_CPUS via tools/lib/perf/include/internal/cpumap.h which is internal. The preferred dependency should be the definition in tools/perf/perf.h. Add the includes of perf.h so that MAX_NR_CPUS can be hidden in libperf. Reviewed-by: Leo Yan Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ben Gainey Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Kyle Meyer Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241206044035.1062032-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork top: Implements BPF-based cpu usage statistics

2023-09-12T20:31:59+00:00

Use BPF to collect statistics on the CPU usage based on perf BPF skeletons. Example usage: # perf kwork top -h Usage: perf kwork top [] -b, --use-bpf Use BPF to measure task cpu usage -C, --cpu list of cpus to profile -i, --input input file name -n, --name event name to profile -s, --sort sort by key(s): rate, runtime, tid --time Time span for analysis (start,stop) # # perf kwork -k sched top -b Starting trace, Hit to stop and report ^C Total : 160702.425 ms, 8 cpus %Cpu(s): 36.00% id, 0.00% hi, 0.00% si %Cpu0 [|||||||||||||||||| 61.66%] %Cpu1 [|||||||||||||||||| 61.27%] %Cpu2 [||||||||||||||||||| 66.40%] %Cpu3 [|||||||||||||||||| 61.28%] %Cpu4 [|||||||||||||||||| 61.82%] %Cpu5 [||||||||||||||||||||||| 77.41%] %Cpu6 [|||||||||||||||||| 61.73%] %Cpu7 [|||||||||||||||||| 63.25%] PID SPID %CPU RUNTIME COMMMAND ------------------------------------------------------------- 0 0 38.72 8089.463 ms [swapper/1] 0 0 38.71 8084.547 ms [swapper/3] 0 0 38.33 8007.532 ms [swapper/0] 0 0 38.26 7992.985 ms [swapper/6] 0 0 38.17 7971.865 ms [swapper/4] 0 0 36.74 7447.765 ms [swapper/7] 0 0 33.59 6486.942 ms [swapper/2] 0 0 22.58 3771.268 ms [swapper/5] 9545 9351 2.48 447.136 ms sched-messaging 9574 9351 2.09 418.583 ms sched-messaging 9724 9351 2.05 372.407 ms sched-messaging 9531 9351 2.01 368.804 ms sched-messaging 9512 9351 2.00 362.250 ms sched-messaging 9514 9351 1.95 357.767 ms sched-messaging 9538 9351 1.86 384.476 ms sched-messaging 9712 9351 1.84 386.490 ms sched-messaging 9723 9351 1.83 380.021 ms sched-messaging 9722 9351 1.82 382.738 ms sched-messaging 9517 9351 1.81 354.794 ms sched-messaging 9559 9351 1.79 344.305 ms sched-messaging 9725 9351 1.77 365.315 ms sched-messaging # perf kwork -k sched top -b -n perf Starting trace, Hit to stop and report ^C Total : 151563.332 ms, 8 cpus %Cpu(s): 26.49% id, 0.00% hi, 0.00% si %Cpu0 [ 0.01%] %Cpu1 [ 0.00%] %Cpu2 [ 0.00%] %Cpu3 [ 0.00%] %Cpu4 [ 0.00%] %Cpu5 [ 0.00%] %Cpu6 [ 0.00%] %Cpu7 [ 0.00%] PID SPID %CPU RUNTIME COMMMAND ------------------------------------------------------------- 9754 9754 0.01 2.303 ms perf # # perf kwork -k sched top -b -C 2,3,4 Starting trace, Hit to stop and report ^C Total : 48016.721 ms, 3 cpus %Cpu(s): 27.82% id, 0.00% hi, 0.00% si %Cpu2 [|||||||||||||||||||||| 74.68%] %Cpu3 [||||||||||||||||||||| 71.06%] %Cpu4 [||||||||||||||||||||| 70.91%] PID SPID %CPU RUNTIME COMMMAND ------------------------------------------------------------- 0 0 29.08 4734.998 ms [swapper/4] 0 0 28.93 4710.029 ms [swapper/3] 0 0 25.31 3912.363 ms [swapper/2] 10248 10158 1.62 264.931 ms sched-messaging 10253 10158 1.62 265.136 ms sched-messaging 10158 10158 1.60 263.013 ms bash 10360 10158 1.49 243.639 ms sched-messaging 10413 10158 1.48 238.604 ms sched-messaging 10531 10158 1.47 234.067 ms sched-messaging 10400 10158 1.47 240.631 ms sched-messaging 10355 10158 1.47 230.586 ms sched-messaging 10377 10158 1.43 234.835 ms sched-messaging 10526 10158 1.42 232.045 ms sched-messaging 10298 10158 1.41 222.396 ms sched-messaging 10410 10158 1.38 221.853 ms sched-messaging 10364 10158 1.38 226.042 ms sched-messaging 10480 10158 1.36 213.633 ms sched-messaging 10370 10158 1.36 223.620 ms sched-messaging 10553 10158 1.34 217.169 ms sched-messaging 10291 10158 1.34 211.516 ms sched-messaging 10251 10158 1.34 218.813 ms sched-messaging 10522 10158 1.33 218.498 ms sched-messaging 10288 10158 1.33 216.787 ms sched-messaging Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-15-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork top: Add statistics on softirq event support

2023-09-12T20:31:59+00:00

Calculate the runtime of the softirq events and subtract it from the corresponding task runtime to improve the precision. Example usage: # perf kwork -k sched,irq,softirq record -- perf record -e cpu-clock -o perf_record.data -a sleep 10 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.467 MB perf_record.data (7154 samples) ] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 2.152 MB perf.data (22846 samples) ] # perf kwork top Total : 136601.588 ms, 8 cpus %Cpu(s): 95.66% id, 0.04% hi, 0.05% si %Cpu0 [ 0.02%] %Cpu1 [ 0.01%] %Cpu2 [| 4.61%] %Cpu3 [ 0.04%] %Cpu4 [ 0.01%] %Cpu5 [||||| 17.31%] %Cpu6 [ 0.51%] %Cpu7 [||| 11.42%] PID %CPU RUNTIME COMMMAND ---------------------------------------------------- 0 99.98 17073.515 ms swapper/4 0 99.98 17072.173 ms swapper/1 0 99.93 17064.229 ms swapper/3 0 99.62 17011.013 ms swapper/0 0 99.47 16985.180 ms swapper/6 0 95.17 16250.874 ms swapper/2 0 88.51 15111.684 ms swapper/7 0 82.62 14108.577 ms swapper/5 4342 33.00 5644.045 ms perf 4344 0.43 74.351 ms perf 16 0.13 22.296 ms rcu_preempt 4345 0.05 10.093 ms perf 4343 0.05 8.769 ms perf 4341 0.02 4.882 ms perf 4095 0.02 4.605 ms kworker/7:1 75 0.02 4.261 ms kworker/2:1 120 0.01 1.909 ms systemd-journal 98 0.01 2.540 ms jbd2/sda-8 61 0.01 3.404 ms kcompactd0 667 0.01 2.542 ms kworker/u16:2 4340 0.00 1.052 ms kworker/7:2 97 0.00 0.489 ms kworker/7:1H 51 0.00 0.209 ms ksoftirqd/7 50 0.00 0.646 ms migration/7 76 0.00 0.753 ms kworker/6:1 45 0.00 0.572 ms migration/6 87 0.00 0.145 ms kworker/5:1H 73 0.00 0.596 ms kworker/5:1 41 0.00 0.041 ms ksoftirqd/5 40 0.00 0.718 ms migration/5 64 0.00 0.115 ms kworker/4:1 35 0.00 0.556 ms migration/4 353 0.00 2.600 ms sshd 74 0.00 0.205 ms kworker/3:1 33 0.00 1.576 ms kworker/3:0H 30 0.00 0.996 ms migration/3 26 0.00 1.665 ms ksoftirqd/2 25 0.00 0.662 ms migration/2 397 0.00 0.057 ms kworker/1:1 20 0.00 1.005 ms migration/1 2909 0.00 1.053 ms kworker/0:2 17 0.00 0.720 ms migration/0 15 0.00 0.039 ms ksoftirqd/0 Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-13-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork top: Add statistics on hardirq event support

2023-09-12T20:31:59+00:00

Calculate the runtime of the hardirq events and subtract it from the corresponding task runtime to improve the precision. Example usage: # perf kwork -k sched,irq record -- perf record -o perf_record.data -a sleep 10 [ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 1.054 MB perf_record.data (18019 samples) ] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.798 MB perf.data (16334 samples) ] # # perf kwork top Total : 139240.869 ms, 8 cpus %Cpu(s): 94.91% id, 0.05% hi %Cpu0 [ 0.05%] %Cpu1 [| 5.00%] %Cpu2 [ 0.43%] %Cpu3 [ 0.57%] %Cpu4 [ 1.19%] %Cpu5 [|||||| 20.46%] %Cpu6 [ 0.48%] %Cpu7 [||| 12.10%] PID %CPU RUNTIME COMMMAND ---------------------------------------------------- 0 99.54 17325.622 ms swapper/2 0 99.54 17327.527 ms swapper/0 0 99.51 17319.909 ms swapper/6 0 99.42 17304.934 ms swapper/3 0 98.80 17197.385 ms swapper/4 0 94.99 16534.991 ms swapper/1 0 87.89 15295.264 ms swapper/7 0 79.53 13843.182 ms swapper/5 4252 36.50 6361.768 ms perf 4256 1.17 205.215 ms bash 151 0.53 93.298 ms systemd-resolve 4254 0.39 69.468 ms perf 423 0.34 59.368 ms bash 412 0.29 51.204 ms sshd 249 0.20 35.288 ms sd-resolve 16 0.17 30.287 ms rcu_preempt 153 0.09 17.266 ms systemd-timesyn 1 0.09 17.078 ms systemd 4253 0.07 12.457 ms perf 4255 0.06 11.559 ms perf 4234 0.03 6.105 ms kworker/u16:1 69 0.03 6.259 ms kworker/1:1H 4251 0.02 4.615 ms perf 4095 0.02 4.890 ms kworker/7:1 61 0.02 4.005 ms kcompactd0 75 0.02 3.546 ms kworker/2:1 97 0.01 3.106 ms kworker/7:1H 98 0.01 1.995 ms jbd2/sda-8 4088 0.01 1.779 ms kworker/u16:3 2909 0.01 1.795 ms kworker/0:2 4246 0.00 1.117 ms kworker/7:2 51 0.00 0.327 ms ksoftirqd/7 50 0.00 0.369 ms migration/7 102 0.00 0.160 ms kworker/6:1H 76 0.00 0.609 ms kworker/6:1 45 0.00 0.779 ms migration/6 87 0.00 0.504 ms kworker/5:1H 73 0.00 1.130 ms kworker/5:1 41 0.00 0.152 ms ksoftirqd/5 40 0.00 0.702 ms migration/5 64 0.00 0.316 ms kworker/4:1 35 0.00 0.791 ms migration/4 353 0.00 2.211 ms sshd 74 0.00 0.272 ms kworker/3:1 30 0.00 0.819 ms migration/3 25 0.00 0.784 ms migration/2 397 0.00 0.539 ms kworker/1:1 21 0.00 1.600 ms ksoftirqd/1 20 0.00 0.773 ms migration/1 17 0.00 1.682 ms migration/0 15 0.00 0.076 ms ksoftirqd/0 Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-12-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork top: Introduce new top utility

2023-09-12T20:31:59+00:00

Some common tools for collecting statistics on CPU usage, such as top, obtain statistics from timer interrupt sampling, and then periodically read statistics from /proc/stat. This method has some deviations: 1. In the tick interrupt, the time between the last tick and the current tick is counted in the current task. However, the task may be running only part of the time. 2. For each task, the top tool periodically reads the /proc/{PID}/status information. For tasks with a short life cycle, it may be missed. In conclusion, the top tool cannot accurately collect statistics on the CPU usage and running time of tasks. The statistical method based on sched_switch tracepoint can accurately calculate the CPU usage of all tasks. This method is applicable to scenarios where performance comparison data is of high precision. Example usage: # perf kwork Usage: perf kwork [] {record|report|latency|timehist|top} -D, --dump-raw-trace dump raw trace in ASCII -f, --force don't complain, do it -k, --kwork list of kwork to profile (irq, softirq, workqueue, sched, etc) -v, --verbose be more verbose (show symbol address, etc) # perf kwork -k sched record -- perf bench sched messaging -g 1 -l 10000 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 1 groups == 40 processes run Total time: 14.074 [sec] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 15.886 MB perf.data (129472 samples) ] # perf kwork top Total : 115708.178 ms, 8 cpus %Cpu(s): 9.78% id %Cpu0 [||||||||||||||||||||||||||| 90.55%] %Cpu1 [||||||||||||||||||||||||||| 90.51%] %Cpu2 [|||||||||||||||||||||||||| 88.57%] %Cpu3 [||||||||||||||||||||||||||| 91.18%] %Cpu4 [||||||||||||||||||||||||||| 91.09%] %Cpu5 [||||||||||||||||||||||||||| 90.88%] %Cpu6 [|||||||||||||||||||||||||| 88.64%] %Cpu7 [||||||||||||||||||||||||||| 90.28%] PID %CPU RUNTIME COMMMAND ---------------------------------------------------- 4113 22.23 3221.547 ms sched-messaging 4105 21.61 3131.495 ms sched-messaging 4119 21.53 3120.937 ms sched-messaging 4103 21.39 3101.614 ms sched-messaging 4106 21.37 3095.209 ms sched-messaging 4104 21.25 3077.269 ms sched-messaging 4115 21.21 3073.188 ms sched-messaging 4109 21.18 3069.022 ms sched-messaging 4111 20.78 3010.033 ms sched-messaging 4114 20.74 3007.073 ms sched-messaging 4108 20.73 3002.137 ms sched-messaging 4107 20.47 2967.292 ms sched-messaging 4117 20.39 2955.335 ms sched-messaging 4112 20.34 2947.080 ms sched-messaging 4118 20.32 2942.519 ms sched-messaging 4121 20.23 2929.865 ms sched-messaging 4110 20.22 2930.078 ms sched-messaging 4122 20.15 2919.542 ms sched-messaging 4120 19.77 2866.032 ms sched-messaging 4116 19.72 2857.660 ms sched-messaging 4127 16.19 2346.334 ms sched-messaging 4142 15.86 2297.600 ms sched-messaging 4141 15.62 2262.646 ms sched-messaging 4136 15.41 2231.408 ms sched-messaging 4130 15.38 2227.008 ms sched-messaging 4129 15.31 2217.692 ms sched-messaging 4126 15.21 2201.711 ms sched-messaging 4139 15.19 2200.722 ms sched-messaging 4137 15.10 2188.633 ms sched-messaging 4134 15.06 2182.082 ms sched-messaging 4132 15.02 2177.530 ms sched-messaging 4131 14.73 2131.973 ms sched-messaging 4125 14.68 2125.439 ms sched-messaging 4128 14.66 2122.255 ms sched-messaging 4123 14.65 2122.113 ms sched-messaging 4135 14.56 2107.144 ms sched-messaging 4133 14.51 2103.549 ms sched-messaging 4124 14.27 2066.671 ms sched-messaging 4140 14.17 2052.251 ms sched-messaging 4138 13.81 2000.361 ms sched-messaging 0 11.42 1652.009 ms swapper/2 0 11.35 1641.694 ms swapper/6 0 9.71 1405.108 ms swapper/7 0 9.48 1372.338 ms swapper/1 0 9.44 1366.013 ms swapper/0 0 9.11 1318.382 ms swapper/5 0 8.90 1287.582 ms swapper/4 0 8.81 1274.356 ms swapper/3 4100 2.61 379.328 ms perf 4101 1.16 169.487 ms perf-exec 151 0.65 94.741 ms systemd-resolve 249 0.36 53.030 ms sd-resolve 153 0.14 21.405 ms systemd-timesyn 1 0.10 16.200 ms systemd 16 0.09 15.785 ms rcu_preempt 4102 0.06 9.727 ms perf 4095 0.03 5.464 ms kworker/7:1 98 0.02 3.231 ms jbd2/sda-8 353 0.02 4.115 ms sshd 75 0.02 3.889 ms kworker/2:1 73 0.01 1.552 ms kworker/5:1 64 0.01 1.591 ms kworker/4:1 74 0.01 1.952 ms kworker/3:1 61 0.01 2.608 ms kcompactd0 397 0.01 1.602 ms kworker/1:1 69 0.01 1.817 ms kworker/1:1H 10 0.01 2.553 ms kworker/u16:0 2909 0.01 2.684 ms kworker/0:2 1211 0.00 0.426 ms kworker/7:0 97 0.00 0.153 ms kworker/7:1H 51 0.00 0.100 ms ksoftirqd/7 120 0.00 0.856 ms systemd-journal 76 0.00 1.414 ms kworker/6:1 46 0.00 0.246 ms ksoftirqd/6 45 0.00 0.164 ms migration/6 41 0.00 0.098 ms ksoftirqd/5 40 0.00 0.207 ms migration/5 86 0.00 1.339 ms kworker/4:1H 36 0.00 0.252 ms ksoftirqd/4 35 0.00 0.090 ms migration/4 31 0.00 0.156 ms ksoftirqd/3 30 0.00 0.073 ms migration/3 26 0.00 0.180 ms ksoftirqd/2 25 0.00 0.085 ms migration/2 21 0.00 0.106 ms ksoftirqd/1 20 0.00 0.118 ms migration/1 302 0.00 1.440 ms systemd-logind 17 0.00 0.132 ms migration/0 15 0.00 0.255 ms ksoftirqd/0 Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-10-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork: Add sched record support

2023-09-12T20:31:59+00:00

The kwork_class type of sched is added to support recording and parsing of sched_switch events. As follows: # perf kwork -h Usage: perf kwork [] {record|report|latency|timehist} -D, --dump-raw-trace dump raw trace in ASCII -f, --force don't complain, do it -k, --kwork list of kwork to profile (irq, softirq, workqueue, sched, etc) -v, --verbose be more verbose (show symbol address, etc) # perf kwork -k sched record true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.083 MB perf.data (47 samples) ] # perf evlist sched:sched_switch dummy:HG # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-8-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork: Add `kwork` and `src_type` to work_init() for 'struct kwork_class'

2023-09-12T20:31:59+00:00

To support different types of reports, two parameters `struct perf_kwork * kwork` and `enum kwork_trace_type src_type` are added to work_init() of struct kwork_class for initialization in different scenarios. No functional change intended. Reviewed-by: Ian Rogers Signed-off-by: Yang Jihong Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Link: https://lore.kernel.org/r/20230812084917.169338-5-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf kwork: Remove includes not needed in kwork.h

2022-10-31T14:06:46+00:00

Leave just some forward declarations for pointers, move the includes to where they are really needed. Signed-off-by: Arnaldo Carvalho de Melo

perf kwork: Implement BPF trace

2022-07-26T19:31:54+00:00

'perf record' generates perf.data, which generates extra interrupts for hard disk, amount of data to be collected increases with time. Using eBPF trace can process the data in kernel, which solves the preceding two problems. Add -b/--use-bpf option for latency and report to support tracing kwork events using eBPF: 1. Create bpf prog and attach to tracepoints, 2. Start tracing after command is entered, 3. After user hit "ctrl+c", stop tracing and report, 4. Support CPU and name filtering. This commit implements the framework code and does not add specific event support. Test cases: # perf kwork rep -h Usage: perf kwork report [] -b, --use-bpf Use BPF to measure kwork runtime -C, --cpu list of cpus to profile -i, --input input file name -n, --name event name to profile -s, --sort sort by key(s): runtime, max, count -S, --with-summary Show summary with statistics --time Time span for analysis (start,stop) # perf kwork lat -h Usage: perf kwork latency [] -b, --use-bpf Use BPF to measure kwork latency -C, --cpu list of cpus to profile -i, --input input file name -n, --name event name to profile -s, --sort sort by key(s): avg, max, count --time Time span for analysis (start,stop) # perf kwork lat -b Unsupported bpf trace class irq # perf kwork rep -b Unsupported bpf trace class irq Signed-off-by: Yang Jihong Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Paul Clarke Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20220709015033.38326-15-yangjihong1@huawei.com [ Simplify work_findnew() ] Signed-off-by: Arnaldo Carvalho de Melo