NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPTIONS FOR PERF SCHED MAP | OPTIONS FOR PERF SCHED TIMEHIST | SEE ALSO | COLOPHON

PERF-SCHED(1)                    perf Manual                   PERF-SCHED(1)

NAME         top

       perf-sched - Tool to trace/measure scheduler properties (latencies)

SYNOPSIS         top

       perf sched {record|latency|map|replay|script|timehist}

DESCRIPTION         top

       There are several variants of perf sched:

           'perf sched record <command>' to record the scheduling events
           of an arbitrary workload.

           'perf sched latency' to report the per task scheduling latencies
           and other scheduling properties of the workload.

           'perf sched script' to see a detailed trace of the workload that
            was recorded (aliased to 'perf script' for now).

           'perf sched replay' to simulate the workload that was recorded
           via perf sched record. (this is done by starting up mockup threads
           that mimic the workload based on the events in the trace. These
           threads can then replay the timings (CPU runtime and sleep patterns)
           of the workload as it occurred when it was recorded - and can repeat
           it a number of times, measuring its performance.)

           'perf sched map' to print a textual context-switching outline of
           workload captured via perf sched record.  Columns stand for
           individual CPUs, and the two-letter shortcuts stand for tasks that
           are running on a CPU. A '*' denotes the CPU that had the event, and
           a dot signals an idle CPU.

           'perf sched timehist' provides an analysis of scheduling events.

           Example usage:
               perf sched record -- sleep 1
               perf sched timehist

           By default it shows the individual schedule events, including the wait
           time (time between sched-out and next sched-in events for the task), the
           task scheduling delay (time between wakeup and actually running) and run
           time for the task:

                       time    cpu  task name             wait time  sch delay   run time
                                    [tid/pid]                (msec)     (msec)     (msec)
             -------------- ------  --------------------  ---------  ---------  ---------
               79371.874569 [0011]  gcc[31949]                0.014      0.000      1.148
               79371.874591 [0010]  gcc[31951]                0.000      0.000      0.024
               79371.874603 [0010]  migration/10[59]          3.350      0.004      0.011
               79371.874604 [0011]  <idle>                    1.148      0.000      0.035
               79371.874723 [0005]  <idle>                    0.016      0.000      1.383
               79371.874746 [0005]  gcc[31949]                0.153      0.078      0.022
           ...

           Times are in msec.usec.

OPTIONS         top

       -i, --input=<file>
           Input file name. (default: perf.data unless stdin is a fifo)

       -v, --verbose
           Be more verbose. (show symbol address, etc)

       -D, --dump-raw-trace=
           Display verbose dump of the sched data.

OPTIONS FOR PERF SCHED MAP         top

       --compact
           Show only CPUs with activity. Helps visualizing on high core
           count systems.

       --cpus
           Show just entries with activities for the given CPUs.

       --color-cpus
           Highlight the given cpus.

       --color-pids
           Highlight the given pids.

OPTIONS FOR PERF SCHED TIMEHIST         top

       -k, --vmlinux=<file>
           vmlinux pathname

       --kallsyms=<file>
           kallsyms pathname

       -g, --no-call-graph
           Do not display call chains if present.

       --max-stack
           Maximum number of functions to display in backtrace, default 5.

       -s, --summary
           Show only a summary of scheduling by thread with min, max, and
           average run times (in sec) and relative stddev.

       -S, --with-summary
           Show all scheduling events followed by a summary by thread with
           min, max, and average run times (in sec) and relative stddev.

       --symfs=<directory>
           Look for files with symbols relative to this directory.

       -V, --cpu-visual
           Show visual aid for sched switches by CPU: i marks idle time, s
           are scheduler events.

       -w, --wakeups
           Show wakeup events.

       -M, --migrations
           Show migration events.

       -n, --next
           Show next task.

       -I, --idle-hist
           Show idle-related events only.

       --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.

       --state
           Show task state when it switched out.

SEE ALSO         top

       perf-record(1)

COLOPHON         top

       This page is part of the perf (Performance analysis tools for Linux
       (in Linux source tree)) project.  Information about the project can
       be found at ⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩.  If
       you have a bug report for this manual page, send it to
       linux-kernel@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩ on
       2017-07-05.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

perf                             05/03/2017                    PERF-SCHED(1)