linux-stable/tools/perf/Documentation/perf-kwork.txt
Yang Jihong bcc8b3e88d perf kwork: Implement perf kwork timehist
Implements framework of perf kwork timehist,
to provide an analysis of kernel work events.

Test cases:

  # perf kwork tim
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        91576.060290       91576.060344  [0000]  (s)RCU:9                             0.055       0.111
        91576.061470       91576.061547  [0000]  (s)SCHED:7                           0.077       0.073
        91576.062604       91576.062697  [0001]  (s)RCU:9                             0.094       0.409
        91576.064443       91576.064517  [0002]  (s)RCU:9                             0.074       0.114
        91576.065144       91576.065211  [0000]  (s)SCHED:7                           0.067       0.058
        91576.066564       91576.066609  [0003]  (s)RCU:9                             0.045       0.110
        91576.068495       91576.068559  [0000]  (s)SCHED:7                           0.064       0.059
        91576.068900       91576.068996  [0004]  (s)RCU:9                             0.096       0.726
        91576.069364       91576.069420  [0002]  (s)RCU:9                             0.056       0.082
        91576.069649       91576.069701  [0004]  (s)RCU:9                             0.052       0.111
        91576.070147       91576.070206  [0000]  (s)SCHED:7                           0.060       0.057
        91576.073147       91576.073202  [0000]  (s)SCHED:7                           0.054       0.060
  <SNIP>

  # perf kwork tim --max-stack 2 -g
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        91576.060290       91576.060344  [0000]  (s)RCU:9                             0.055       0.111   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.061470       91576.061547  [0000]  (s)SCHED:7                           0.077       0.073   irq_exit_rcu <- sysvec_call_function_single
        91576.062604       91576.062697  [0001]  (s)RCU:9                             0.094       0.409   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.064443       91576.064517  [0002]  (s)RCU:9                             0.074       0.114   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.065144       91576.065211  [0000]  (s)SCHED:7                           0.067       0.058   irq_exit_rcu <- sysvec_call_function_single
        91576.066564       91576.066609  [0003]  (s)RCU:9                             0.045       0.110   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.068495       91576.068559  [0000]  (s)SCHED:7                           0.064       0.059   irq_exit_rcu <- sysvec_call_function_single
        91576.068900       91576.068996  [0004]  (s)RCU:9                             0.096       0.726   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.069364       91576.069420  [0002]  (s)RCU:9                             0.056       0.082   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.069649       91576.069701  [0004]  (s)RCU:9                             0.052       0.111   irq_exit_rcu <- sysvec_apic_timer_interrupt
  <SNIP>

Committer testing:

  # perf kwork -k workqueue timehist | head -40
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        26520.211825       26520.211832  [0019]  (w)free_work                         0.007       0.004
        26520.212929       26520.212934  [0020]  (w)free_work                         0.005       0.004
        26520.213226       26520.213228  [0014]  (w)kfree_rcu_work                    0.002       0.004
        26520.214057       26520.214061  [0021]  (w)free_work                         0.004       0.004
        26520.221239       26520.221241  [0007]  (w)kfree_rcu_work                    0.002       0.009
        26520.223232       26520.223238  [0013]  (w)psi_avgs_work                     0.005       0.006
        26520.230057       26520.230060  [0020]  (w)free_work                         0.003       0.003
        26520.270428       26520.270434  [0015]  (w)free_work                         0.006       0.004
        26520.270546       26520.270550  [0014]  (w)free_work                         0.004       0.003
        26520.281626       26520.281629  [0015]  (w)free_work                         0.003       0.002
        26520.287225       26520.287230  [0012]  (w)psi_avgs_work                     0.005       0.008
        26520.287231       26520.287235  [0001]  (w)psi_avgs_work                     0.004       0.011
        26520.287236       26520.287239  [0001]  (w)psi_avgs_work                     0.003       0.012
        26520.329488       26520.329492  [0024]  (w)free_work                         0.004       0.004
        26520.330600       26520.330605  [0007]  (w)free_work                         0.005       0.004
        26520.334218       26520.334218  [0007]  (w)kfree_rcu_monitor                 0.001       0.002
        26520.335220       26520.335221  [0005]  (w)kfree_rcu_monitor                 0.001       0.004
        26520.343980       26520.343985  [0007]  (w)free_work                         0.005       0.002
        26520.345093       26520.345097  [0006]  (w)free_work                         0.004       0.003
        26520.351233       26520.351238  [0027]  (w)psi_avgs_work                     0.005       0.008
        26520.353228       26520.353229  [0007]  (w)kfree_rcu_work                    0.001       0.002
        26520.353229       26520.353231  [0005]  (w)kfree_rcu_work                    0.001       0.006
        26520.382381       26520.382383  [0006]  (w)free_work                         0.003       0.002
        26520.386547       26520.386548  [0006]  (w)free_work                         0.002       0.001
        26520.391243       26520.391245  [0015]  (w)console_callback                  0.002       0.016
        26520.415369       26520.415621  [0027]  (w)btrfs_work_helper                 0.252
        26520.415351       26520.416174  [0002]  (w)btrfs_work_helper                 0.823       0.037
        26520.415343       26520.416304  [0031]  (w)btrfs_work_helper                 0.961
        26520.415335       26520.417078  [0001]  (w)btrfs_work_helper                 1.743
        26520.415250       26520.417564  [0002]  (w)wb_workfn                         2.314
        26520.424777       26520.424787  [0002]  (w)btrfs_work_helper                 0.010
        26520.424788       26520.424798  [0002]  (w)btrfs_work_helper                 0.010
        26520.424790       26520.424805  [0001]  (w)btrfs_work_helper                 0.016       0.016
        26520.424801       26520.424807  [0002]  (w)btrfs_work_helper                 0.006
        26520.424809       26520.424831  [0002]  (w)btrfs_work_helper                 0.022       0.030
        26520.424824       26520.424835  [0027]  (w)btrfs_work_helper                 0.011
        26520.424809       26520.424867  [0001]  (w)btrfs_work_helper                 0.059       0.032
  #

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-14-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-07-26 16:31:54 -03:00

170 lines
4.8 KiB
Text

perf-kowrk(1)
=============
NAME
----
perf-kwork - Tool to trace/measure kernel work properties (latencies)
SYNOPSIS
--------
[verse]
'perf kwork' {record}
DESCRIPTION
-----------
There are several variants of 'perf kwork':
'perf kwork record <command>' to record the kernel work
of an arbitrary workload.
'perf kwork report' to report the per kwork runtime.
'perf kwork latency' to report the per kwork latencies.
'perf kwork timehist' provides an analysis of kernel work events.
Example usage:
perf kwork record -- sleep 1
perf kwork report
perf kwork latency
perf kwork timehist
By default it shows the individual work events such as irq, workqeueu,
including the run time and delay (time between raise and actually entry):
Runtime start Runtime end Cpu Kwork name Runtime Delaytime
(TYPE)NAME:NUM (msec) (msec)
----------------- ----------------- ------ ------------------------- ---------- ----------
1811186.976062 1811186.976327 [0000] (s)RCU:9 0.266 0.114
1811186.978452 1811186.978547 [0000] (s)SCHED:7 0.095 0.171
1811186.980327 1811186.980490 [0000] (s)SCHED:7 0.162 0.083
1811186.981221 1811186.981271 [0000] (s)SCHED:7 0.050 0.077
1811186.984267 1811186.984318 [0000] (s)SCHED:7 0.051 0.075
1811186.987252 1811186.987315 [0000] (s)SCHED:7 0.063 0.081
1811186.987785 1811186.987843 [0006] (s)RCU:9 0.058 0.645
1811186.988319 1811186.988383 [0000] (s)SCHED:7 0.064 0.143
1811186.989404 1811186.989607 [0002] (s)TIMER:1 0.203 0.111
1811186.989660 1811186.989732 [0002] (s)SCHED:7 0.072 0.310
1811186.991295 1811186.991407 [0002] eth0:10 0.112
1811186.991639 1811186.991734 [0002] (s)NET_RX:3 0.095 0.277
1811186.989860 1811186.991826 [0002] (w)vmstat_shepherd 1.966 0.345
...
Times are in msec.usec.
OPTIONS
-------
-D::
--dump-raw-trace=::
Display verbose dump of the sched data.
-f::
--force::
Don't complain, do it.
-k::
--kwork::
List of kwork to profile (irq, softirq, workqueue, etc)
-v::
--verbose::
Be more verbose. (show symbol address, etc)
OPTIONS for 'perf kwork report'
----------------------------
-C::
--cpu::
Only show events for the given CPU(s) (comma separated list).
-i::
--input::
Input file name. (default: perf.data unless stdin is a fifo)
-n::
--name::
Only show events for the given name.
-s::
--sort::
Sort by key(s): runtime, max, count
-S::
--with-summary::
Show summary with statistics
--time::
Only analyze samples within given time window: <start>,<stop>. Times
have the format seconds.microseconds. If start is not given (i.e., time
string is ',x.y') then analysis starts at the beginning of the file. If
stop time is not given (i.e, time string is 'x.y,') then analysis goes
to end of file.
OPTIONS for 'perf kwork latency'
----------------------------
-C::
--cpu::
Only show events for the given CPU(s) (comma separated list).
-i::
--input::
Input file name. (default: perf.data unless stdin is a fifo)
-n::
--name::
Only show events for the given name.
-s::
--sort::
Sort by key(s): avg, max, count
--time::
Only analyze samples within given time window: <start>,<stop>. Times
have the format seconds.microseconds. If start is not given (i.e., time
string is ',x.y') then analysis starts at the beginning of the file. If
stop time is not given (i.e, time string is 'x.y,') then analysis goes
to end of file.
OPTIONS for 'perf kwork timehist'
---------------------------------
-C::
--cpu::
Only show events for the given CPU(s) (comma separated list).
-g::
--call-graph::
Display call chains if present (default off).
-i::
--input::
Input file name. (default: perf.data unless stdin is a fifo)
-k::
--vmlinux=<file>::
Vmlinux pathname
-n::
--name::
Only show events for the given name.
--kallsyms=<file>::
Kallsyms pathname
--max-stack::
Maximum number of functions to display in backtrace, default 5.
--symfs=<directory>::
Look for files with symbols relative to this directory.
--time::
Only analyze samples within given time window: <start>,<stop>. Times
have the format seconds.microseconds. If start is not given (i.e., time
string is ',x.y') then analysis starts at the beginning of the file. If
stop time is not given (i.e, time string is 'x.y,') then analysis goes
to end of file.
SEE ALSO
--------
linkperf:perf-record[1]