tools/perf/Documentation/perf-kwork.txt

Source file repositories/reference/linux-study-clean/tools/perf/Documentation/perf-kwork.txt

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Linux kernel
Corpus path
tools/perf/Documentation/perf-kwork.txt
Extension
.txt
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6134 bytes
Lines
218
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

perf-kwork(1)
=============

NAME
----
perf-kwork - Tool to trace/measure kernel work properties (latencies)

SYNOPSIS
--------
[verse]
'perf kwork' {record|report|latency|timehist|top}

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.

  'perf kwork top' to report the task cpu usage.

    Example usage:
        perf kwork record -- sleep 1
        perf kwork report
        perf kwork report -b
        perf kwork latency
        perf kwork latency -b
        perf kwork timehist
        perf kwork top
        perf kwork top -b

   By default it shows the individual work events such as irq, workqueue,
   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.

Annotation

Implementation Notes