tools/perf/Documentation/perf-sched.txt

   1 perf-sched(1)
   2 ==============
   3
   4 NAME
   5 ----
   6 perf-sched - Tool to trace/measure scheduler properties (latencies)
   7
   8 SYNOPSIS
   9 --------
  10 [verse]
  11 'perf sched' {record|latency|map|replay|script|timehist}
  12
  13 DESCRIPTION
  14 -----------
  15 There are several variants of 'perf sched':
  16
  17   'perf sched record <command>' to record the scheduling events
  18   of an arbitrary workload.
  19
  20   'perf sched latency' to report the per task scheduling latencies
  21   and other scheduling properties of the workload.
  22
  23   'perf sched script' to see a detailed trace of the workload that
  24    was recorded (aliased to 'perf script' for now).
  25
  26   'perf sched replay' to simulate the workload that was recorded
  27   via perf sched record. (this is done by starting up mockup threads
  28   that mimic the workload based on the events in the trace. These
  29   threads can then replay the timings (CPU runtime and sleep patterns)
  30   of the workload as it occurred when it was recorded - and can repeat
  31   it a number of times, measuring its performance.)
  32
  33   'perf sched map' to print a textual context-switching outline of
  34   workload captured via perf sched record.  Columns stand for
  35   individual CPUs, and the two-letter shortcuts stand for tasks that
  36   are running on a CPU. A '*' denotes the CPU that had the event, and
  37   a dot signals an idle CPU.
  38
  39   'perf sched timehist' provides an analysis of scheduling events.
  40
  41     Example usage:
  42         perf sched record -- sleep 1
  43         perf sched timehist
  44
  45    By default it shows the individual schedule events, including the wait
  46    time (time between sched-out and next sched-in events for the task), the
  47    task scheduling delay (time between wakeup and actually running) and run
  48    time for the task:
  49
  50                 time    cpu  task name             wait time  sch delay   run time
  51                              [tid/pid]                (msec)     (msec)     (msec)
  52       -------------- ------  --------------------  ---------  ---------  ---------
  53         79371.874569 [0011]  gcc[31949]                0.014      0.000      1.148
  54         79371.874591 [0010]  gcc[31951]                0.000      0.000      0.024
  55         79371.874603 [0010]  migration/10[59]          3.350      0.004      0.011
  56         79371.874604 [0011]  <idle>                    1.148      0.000      0.035
  57         79371.874723 [0005]  <idle>                    0.016      0.000      1.383
  58         79371.874746 [0005]  gcc[31949]                0.153      0.078      0.022
  59     ...
  60
  61    Times are in msec.usec.
  62
  63 OPTIONS
  64 -------
  65 -i::
  66 --input=<file>::
  67         Input file name. (default: perf.data unless stdin is a fifo)
  68
  69 -v::
  70 --verbose::
  71         Be more verbose. (show symbol address, etc)
  72
  73 -D::
  74 --dump-raw-trace=::
  75         Display verbose dump of the sched data.
  76
  77 OPTIONS for 'perf sched map'
  78 ----------------------------
  79
  80 --compact::
  81         Show only CPUs with activity. Helps visualizing on high core
  82         count systems.
  83
  84 --cpus::
  85         Show just entries with activities for the given CPUs.
  86
  87 --color-cpus::
  88         Highlight the given cpus.
  89
  90 --color-pids::
  91         Highlight the given pids.
  92
  93 OPTIONS for 'perf sched timehist'
  94 ---------------------------------
  95 -k::
  96 --vmlinux=<file>::
  97     vmlinux pathname
  98
  99 --kallsyms=<file>::
 100     kallsyms pathname
 101
 102 -g::
 103 --no-call-graph::
 104         Do not display call chains if present.
 105
 106 --max-stack::
 107         Maximum number of functions to display in backtrace, default 5.
 108
 109 -s::
 110 --summary::
 111     Show only a summary of scheduling by thread with min, max, and average
 112     run times (in sec) and relative stddev.
 113
 114 -S::
 115 --with-summary::
 116     Show all scheduling events followed by a summary by thread with min,
 117     max, and average run times (in sec) and relative stddev.
 118
 119 --symfs=<directory>::
 120     Look for files with symbols relative to this directory.
 121
 122 -V::
 123 --cpu-visual::
 124         Show visual aid for sched switches by CPU: 'i' marks idle time,
 125         's' are scheduler events.
 126
 127 -w::
 128 --wakeups::
 129         Show wakeup events.
 130
 131 -M::
 132 --migrations::
 133         Show migration events.
 134
 135 -n::
 136 --next::
 137         Show next task.
 138
 139 -I::
 140 --idle-hist::
 141         Show idle-related events only.
 142
 143 --time::
 144         Only analyze samples within given time window: <start>,<stop>. Times
 145         have the format seconds.microseconds. If start is not given (i.e., time
 146         string is ',x.y') then analysis starts at the beginning of the file. If
 147         stop time is not given (i.e, time string is 'x.y,') then analysis goes
 148         to end of file.
 149
 150 --state::
 151         Show task state when it switched out.
 152
 153 SEE ALSO
 154 --------
 155 linkperf:perf-record[1]