Re: [RFC v1 00/16] perf kwork: Implement perf kwork top

From: Yang Jihong
Date: Tue Sep 05 2023 - 12:52:24 EST

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In reply to: Ian Rogers: "Re: [RFC v1 00/16] perf kwork: Implement perf kwork top"
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Hello,

On 2023/9/4 22:54, Ian Rogers wrote:

On Mon, Sep 4, 2023 at 4:59 AM Yang Jihong <yangjihong1@xxxxxxxxxx> wrote:

Hello,

On 2023/9/4 13:13, Ian Rogers wrote:

On Sat, Aug 12, 2023 at 1:52 AM Yang Jihong <yangjihong1@xxxxxxxxxx> wrote:

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.

In addition to parsing the perf.data file, the provides BPF-based CPU usage
statistics to reduce the load of the perf process.

Example usage:

# perf kwork top -h

Usage: perf kwork top [<options>]

-C, --cpu <cpu> list of cpus to profile
-i, --input <file> input file name
-n, --name <name> event name to profile
-s, --sort <key[,key2...]>
sort by key(s): rate, runtime, tid
--time <str> Time span for analysis (start,stop)

# ./perf kwork -k sched,irq,softirq 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: 1.854 [sec]
[ perf record: Woken up 13 times to write data ]
[ perf record: Captured and wrote 27.436 MB perf.data (235986 samples) ]
#
# perf kwork top

Total : 22419.068 ms, 12 cpus
%Cpu(s): 17.99% id, 0.00% hi, 0.09% si
%Cpu0 [|||||||||||||||||||||||| 82.56%]
%Cpu1 [|||||||||||||||||||||||| 81.73%]
%Cpu2 [|||||||||||||||||||||||| 83.00%]
%Cpu3 [|||||||||||||||||||||||| 81.01%]
%Cpu4 [|||||||||||||||||||||||| 81.66%]
%Cpu5 [|||||||||||||||||||||||| 82.10%]
%Cpu6 [|||||||||||||||||||||||| 81.65%]
%Cpu7 [|||||||||||||||||||||||| 82.00%]
%Cpu8 [|||||||||||||||||||||||| 82.54%]
%Cpu9 [|||||||||||||||||||||||| 81.02%]
%Cpu10 [|||||||||||||||||||||||| 81.78%]
%Cpu11 [|||||||||||||||||||||||| 81.87%]

PID %CPU RUNTIME COMMMAND
----------------------------------------------------
2913025 27.62 516.976 ms sched-messaging
2913017 27.56 516.273 ms sched-messaging
2913018 27.56 516.152 ms sched-messaging
2913008 27.54 515.447 ms sched-messaging
2913010 27.50 514.890 ms sched-messaging
2913007 27.48 514.411 ms sched-messaging
2913015 27.36 512.563 ms sched-messaging
2913026 27.35 512.198 ms sched-messaging
2913011 27.32 511.632 ms sched-messaging
2913014 27.32 511.381 ms sched-messaging
2913012 27.30 511.138 ms sched-messaging
2913013 27.30 511.109 ms sched-messaging
2913009 27.30 510.997 ms sched-messaging
2913019 27.25 510.488 ms sched-messaging
2913021 27.23 509.661 ms sched-messaging
2913023 27.21 509.400 ms sched-messaging
2913020 27.20 509.677 ms sched-messaging
2913022 27.19 509.061 ms sched-messaging
2913016 27.18 509.231 ms sched-messaging
2913024 27.18 509.108 ms sched-messaging
2912999 21.79 407.929 ms sched-messaging
2913000 21.78 408.045 ms sched-messaging
2912998 21.75 407.579 ms sched-messaging
2912993 21.69 406.166 ms sched-messaging
2912991 21.59 404.378 ms sched-messaging
2912992 21.57 403.845 ms sched-messaging
2913005 21.56 403.715 ms sched-messaging
2913001 21.55 403.803 ms sched-messaging
2912990 21.54 403.601 ms sched-messaging
2912994 21.52 403.087 ms sched-messaging
2912995 21.49 402.421 ms sched-messaging
2912996 21.48 402.666 ms sched-messaging
2912989 21.46 402.303 ms sched-messaging
2913003 21.46 402.034 ms sched-messaging
2912988 21.44 401.820 ms sched-messaging
2913004 21.37 400.242 ms sched-messaging
2912987 21.28 398.512 ms sched-messaging
2913002 21.27 398.759 ms sched-messaging
2912997 21.27 398.518 ms sched-messaging
2913006 21.23 397.888 ms sched-messaging
0 18.89 353.061 ms swapper/3
0 18.89 353.026 ms swapper/9
0 18.26 341.190 ms swapper/6
0 18.25 341.048 ms swapper/4
0 18.13 338.844 ms swapper/10
0 18.12 338.686 ms swapper/1
0 18.05 337.333 ms swapper/11
0 17.92 334.903 ms swapper/7
0 17.80 332.691 ms swapper/5
0 17.38 324.762 ms swapper/8
0 17.29 323.102 ms swapper/0
0 16.89 315.630 ms swapper/2
2912984 2.10 39.452 ms perf
2912985 0.73 14.004 ms sched-messaging
660381 0.14 3.527 ms containerd
3006112 0.07 1.402 ms redis-server
2904655 0.05 1.071 ms kworker/0:0
659822 0.03 1.729 ms containerd
659824 0.03 1.346 ms containerd
1053 0.01 0.353 ms zabbix_agentd
2895571 0.01 0.349 ms kworker/8:1
10 0.00 0.535 ms rcu_sched
2912192 0.00 0.272 ms kworker/u24:2
2903540 0.00 0.182 ms sshd
801 0.00 0.120 ms jbd2/sda4-8
2929605 0.00 0.108 ms grpc_global_tim
2912986 0.00 0.075 ms perf
2897765 0.00 0.073 ms kworker/7:1
2912817 0.00 0.070 ms kworker/2:1
391756 0.00 0.067 ms grpc_global_tim
2901459 0.00 0.056 ms kworker/3:0
2908185 0.00 0.052 ms kworker/10:1
2901521 0.00 0.050 ms kworker/6:1
2902444 0.00 0.046 ms kworker/5:1
2898513 0.00 0.041 ms kworker/1:1
2912280 0.00 0.039 ms kworker/11:3
1057 0.00 0.037 ms zabbix_agentd
2908010 0.00 0.037 ms kworker/9:3
2912951 0.00 0.036 ms kworker/4:3
793 0.00 0.027 ms multipathd
42 0.00 0.023 ms ksoftirqd/5
9 0.00 0.022 ms ksoftirqd/0
24 0.00 0.019 ms ksoftirqd/2
59 0.00 0.019 ms migration/8
2929607 0.00 0.018 ms wecode-db
29 0.00 0.012 ms migration/3
11 0.00 0.012 ms migration/0
65 0.00 0.012 ms migration/9
17 0.00 0.011 ms migration/1
71 0.00 0.011 ms migration/10
53 0.00 0.011 ms migration/7
23 0.00 0.011 ms migration/2
47 0.00 0.011 ms migration/6
789 0.00 0.010 ms multipathd
35 0.00 0.010 ms migration/4
480 0.00 0.009 ms kworker/4:1H
41 0.00 0.008 ms migration/5
54 0.00 0.006 ms ksoftirqd/7
36 0.00 0.005 ms ksoftirqd/4
72 0.00 0.005 ms ksoftirqd/10
66 0.00 0.005 ms ksoftirqd/9
30 0.00 0.004 ms ksoftirqd/3
2898362 0.00 0.003 ms kworker/u24:0

# perf kwork top -C 2,4,5

Total : 5604.885 ms, 3 cpus
%Cpu(s): 17.65% id, 0.00% hi, 0.09% si
%Cpu2 [|||||||||||||||||||||||| 83.00%]
%Cpu4 [|||||||||||||||||||||||| 81.66%]
%Cpu5 [|||||||||||||||||||||||| 82.10%]

PID %CPU RUNTIME COMMMAND
----------------------------------------------------
0 18.25 341.048 ms swapper/4
0 17.80 332.691 ms swapper/5
0 16.89 315.630 ms swapper/2
2913012 8.99 168.201 ms sched-messaging
2913021 8.74 163.456 ms sched-messaging
2913026 8.34 156.120 ms sched-messaging
2913010 8.14 152.372 ms sched-messaging
2913007 7.74 144.754 ms sched-messaging
2913016 7.42 138.977 ms sched-messaging
2913022 7.28 136.279 ms sched-messaging
2913013 7.00 130.894 ms sched-messaging
2913019 6.96 130.455 ms sched-messaging
2913023 6.91 129.364 ms sched-messaging
2913008 6.47 121.331 ms sched-messaging
2913018 6.47 121.124 ms sched-messaging
2912994 6.42 120.213 ms sched-messaging
2913025 6.42 120.140 ms sched-messaging
2913020 6.37 119.386 ms sched-messaging
2913011 6.35 118.921 ms sched-messaging
2913014 6.24 116.779 ms sched-messaging
2913009 6.01 112.661 ms sched-messaging
2913005 5.96 111.587 ms sched-messaging
2913003 5.94 111.142 ms sched-messaging
2913024 5.87 109.876 ms sched-messaging
2912988 5.84 109.396 ms sched-messaging
2912987 5.80 108.550 ms sched-messaging
2912990 5.51 103.322 ms sched-messaging
2912993 5.45 102.045 ms sched-messaging
2912996 5.42 101.622 ms sched-messaging
2913006 5.42 101.592 ms sched-messaging
2913000 5.41 101.511 ms sched-messaging
2913002 5.41 101.420 ms sched-messaging
2912997 5.40 101.315 ms sched-messaging
2913004 5.33 99.872 ms sched-messaging
2913015 5.29 99.252 ms sched-messaging
2913017 5.22 97.822 ms sched-messaging
2912991 5.11 95.773 ms sched-messaging
2912992 5.11 95.579 ms sched-messaging
2913001 5.07 95.033 ms sched-messaging
2912989 4.93 92.425 ms sched-messaging
2912995 4.85 90.892 ms sched-messaging
2912998 4.78 89.617 ms sched-messaging
2912999 4.56 85.576 ms sched-messaging
3006112 0.07 1.402 ms redis-server
660381 0.02 0.566 ms containerd
2912984 0.02 0.452 ms perf
659824 0.01 0.369 ms containerd
659822 0.00 0.316 ms containerd
10 0.00 0.176 ms rcu_sched
801 0.00 0.120 ms jbd2/sda4-8
2912985 0.00 0.107 ms sched-messaging
2912986 0.00 0.075 ms perf
2912817 0.00 0.070 ms kworker/2:1
2912192 0.00 0.056 ms kworker/u24:2
2929605 0.00 0.046 ms grpc_global_tim
2902444 0.00 0.046 ms kworker/5:1
2912951 0.00 0.036 ms kworker/4:3
42 0.00 0.023 ms ksoftirqd/5
24 0.00 0.019 ms ksoftirqd/2
23 0.00 0.011 ms migration/2
35 0.00 0.010 ms migration/4
480 0.00 0.009 ms kworker/4:1H
41 0.00 0.008 ms migration/5
36 0.00 0.005 ms ksoftirqd/4

# perf kwork top -n perf

Total : 22419.068 ms, 12 cpus
%Cpu(s): 17.99% id, 0.00% hi, 0.09% si
%Cpu0 [ 0.00%]
%Cpu1 [ 0.00%]
%Cpu2 [ 0.02%]
%Cpu3 [ 0.00%]
%Cpu4 [ 0.00%]
%Cpu5 [ 0.00%]
%Cpu6 [ 0.00%]
%Cpu7 [ 0.00%]
%Cpu8 [ 0.03%]
%Cpu9 [ 0.09%]
%Cpu10 [ 0.00%]
%Cpu11 [ 1.96%]

PID %CPU RUNTIME COMMMAND
----------------------------------------------------
2912984 2.10 39.452 ms perf
2912986 0.00 0.075 ms perf

# perf kwork top -s tid -n sched-messaging

Total : 22419.068 ms, 12 cpus
%Cpu(s): 17.99% id, 0.00% hi, 0.09% si
%Cpu0 [|||||||||||||||||||||||| 81.80%]
%Cpu1 [|||||||||||||||||||||||| 81.65%]
%Cpu2 [|||||||||||||||||||||||| 82.88%]
%Cpu3 [|||||||||||||||||||||||| 80.96%]
%Cpu4 [|||||||||||||||||||||||| 81.64%]
%Cpu5 [|||||||||||||||||||||||| 82.04%]
%Cpu6 [|||||||||||||||||||||||| 81.63%]
%Cpu7 [|||||||||||||||||||||||| 81.97%]
%Cpu8 [|||||||||||||||||||||||| 82.43%]
%Cpu9 [|||||||||||||||||||||||| 80.86%]
%Cpu10 [|||||||||||||||||||||||| 81.72%]
%Cpu11 [||||||||||||||||||||||| 79.89%]

PID %CPU RUNTIME COMMMAND
----------------------------------------------------
2912985 0.04 1.111 ms sched-messaging
2912987 21.28 398.512 ms sched-messaging
2912988 21.44 401.820 ms sched-messaging
2912989 21.46 402.303 ms sched-messaging
2912990 21.54 403.601 ms sched-messaging
2912991 21.59 404.378 ms sched-messaging
2912992 21.57 403.845 ms sched-messaging
2912993 21.69 406.166 ms sched-messaging
2912994 21.52 403.087 ms sched-messaging
2912995 21.49 402.421 ms sched-messaging
2912996 21.48 402.666 ms sched-messaging
2912997 21.27 398.518 ms sched-messaging
2912998 21.75 407.579 ms sched-messaging
2912999 21.79 407.929 ms sched-messaging
2913000 21.78 408.045 ms sched-messaging
2913001 21.55 403.803 ms sched-messaging
2913002 21.27 398.759 ms sched-messaging
2913003 21.46 402.034 ms sched-messaging
2913004 21.37 400.242 ms sched-messaging
2913005 21.56 403.715 ms sched-messaging
2913006 21.23 397.888 ms sched-messaging
2913007 27.48 514.411 ms sched-messaging
2913008 27.54 515.447 ms sched-messaging
2913009 27.30 510.997 ms sched-messaging
2913010 27.50 514.890 ms sched-messaging
2913011 27.32 511.632 ms sched-messaging
2913012 27.30 511.138 ms sched-messaging
2913013 27.30 511.109 ms sched-messaging
2913014 27.32 511.381 ms sched-messaging
2913015 27.36 512.563 ms sched-messaging
2913016 27.18 509.231 ms sched-messaging
2913017 27.56 516.273 ms sched-messaging
2913018 27.56 516.152 ms sched-messaging
2913019 27.25 510.488 ms sched-messaging
2913020 27.20 509.677 ms sched-messaging
2913021 27.23 509.661 ms sched-messaging
2913022 27.19 509.061 ms sched-messaging
2913023 27.21 509.400 ms sched-messaging
2913024 27.18 509.108 ms sched-messaging
2913025 27.62 516.976 ms sched-messaging
2913026 27.35 512.198 ms sched-messaging

# perf kwork top -b
Starting trace, Hit <Ctrl+C> to stop and report
^C
Total : 89209.004 ms, 4 cpus
%Cpu(s): 13.47% id, 0.01% hi, 0.24% si
%Cpu0 [||||||||||||||||||||||||| 86.08%]
%Cpu1 [|||||||||||||||||||||||||| 87.08%]
%Cpu2 [||||||||||||||||||||||||| 86.10%]
%Cpu3 [||||||||||||||||||||||||| 85.86%]

PID SPID %CPU RUNTIME COMMMAND
-------------------------------------------------------------
0 0 13.86 3092.482 ms [swapper/3]
0 0 13.71 3057.756 ms [swapper/0]
0 0 13.65 3044.987 ms [swapper/2]
0 0 12.63 2818.079 ms [swapper/1]
320 320 1.32 295.427 ms bash
414 320 1.09 247.658 ms sched-messaging
678 320 1.09 246.881 ms sched-messaging
354 320 1.09 246.683 ms sched-messaging
409 320 1.08 246.839 ms sched-messaging
554 320 1.07 243.045 ms sched-messaging
405 320 1.04 237.340 ms sched-messaging
525 320 1.04 235.718 ms sched-messaging
486 320 1.03 235.369 ms sched-messaging
714 320 1.03 235.142 ms sched-messaging
435 320 1.03 233.290 ms sched-messaging
408 320 1.03 231.687 ms sched-messaging
716 320 1.02 233.513 ms sched-messaging
453 320 1.02 233.181 ms sched-messaging
522 320 1.02 230.101 ms sched-messaging
651 320 1.02 229.554 ms sched-messaging
418 320 1.01 231.359 ms sched-messaging
644 320 1.01 229.848 ms sched-messaging
535 320 1.01 229.655 ms sched-messaging
536 320 1.01 229.147 ms sched-messaging
410 320 1.01 227.700 ms sched-messaging
689 320 1.00 227.988 ms sched-messaging
412 320 1.00 227.052 ms sched-messaging
489 320 1.00 226.374 ms sched-messaging
521 320 1.00 225.499 ms sched-messaging
530 320 1.00 225.262 ms sched-messaging
681 320 1.00 225.187 ms sched-messaging
415 320 0.99 225.714 ms sched-messaging
643 320 0.99 225.090 ms sched-messaging
325 320 0.99 223.385 ms sched-messaging
498 320 0.99 222.936 ms sched-messaging
413 320 0.98 225.213 ms sched-messaging
645 320 0.98 223.211 ms sched-messaging
544 320 0.98 222.714 ms sched-messaging
441 320 0.98 222.590 ms sched-messaging
697 320 0.98 222.426 ms sched-messaging
523 320 0.98 221.841 ms sched-messaging
402 320 0.98 221.776 ms sched-messaging
<SNIP>

Yang Jihong (16):
perf kwork: Fix incorrect and missing free atom in work_push_atom()
perf kwork: Add the supported subcommands to the document
perf kwork: Set ordered_events for perf_tool
perf kwork: Add `kwork` and `src_type` to work_init() for struct
kwork_class
perf kwork: Overwrite original atom in the list when a new atom is
pushed.
perf kwork: Set default events list if not specified in
setup_event_list()
perf kwork: Add sched record support
perf kwork: Add `root` parameter to work_sort()
perf kwork: Implement perf kwork top
perf evsel: Add evsel__intval_common() helper
perf kwork top: Add statistics on hardirq event support
perf kwork top: Add statistics on softirq event support
perf kwork top: Add -C/--cpu -i/--input -n/--name -s/--sort --time
options
perf kwork top: Implements BPF-based cpu usage statistics
perf kwork top: Add BPF-based statistics on hardirq event support
perf kwork top: Add BPF-based statistics on softirq event support

Besides documentation nits, series:
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks for reivew.

Whilst looking at the series, could we clean up
tools/perf/util/kwork.h ? Generally none of the structs are commented.

Okay, I'll put up a separate patch and add comments about it.

Some like:
> struct kwork_atom {
struct list_head list;
u64 time;
struct kwork_atom *prev;

void *page_addr;
unsigned long bit_inpage;
};

Why is it an atom? Why is there a prev when the kwork_atom is also on
a list (which has a prev) ?

An atom indicates a minimum granularity event.
For example, an "irq_hander_entry" event of an IRQ whose irqnum==10 is
an atom.

The prev member is used to store the sequence of events.
For example, the sequence of events is as follows:
raise -> entry -> exit

Then:
entry_atom->prev = raise_atom

This relationship needs to be saved because need to calculate latency
time and running time at the same time in the "perf kwork timehist"

Thanks Yang, this is good context. Could it be added to the header

Okay, I can submit a separate patch with comments.

file? I'm also wondering at some point we should start generating
kerneldoc from comments in the code. I don't know if you want to look
into kerneldoc style comments.

Of course, would you like to tell me how to do it?
Not just perf kwork, but the whole perf tool code, I can do some work on this.

Thanks,
Ian

Thanks,
Yang

.

Next message: Luca Weiss: "Re: [PATCH 04/11] arm64: dts: qcom: pm7250b: make SID configurable"
Previous message: Matti Vaittinen: "[PATCH] kernel/reboot: document function parameter"
In reply to: Ian Rogers: "Re: [RFC v1 00/16] perf kwork: Implement perf kwork top"
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