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

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

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

DESCRIPTION
       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
       -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.

       -f, --force
           Don't complain, do it.

OPTIONS FOR PERF SCHED MAP
       --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
       -k, --vmlinux=<file>
           vmlinux pathname

       --kallsyms=<file>
           kallsyms pathname

       -g, --call-graph
           Display call chains if present (default on).

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

       -C=, --cpu=
           Only show events for the given CPU(s) (comma separated list).

       -p=, --pid=
           Only show events for given process ID (comma separated list).

       -t=, --tid=
           Only show events for given thread ID (comma separated list).

       -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
       perf-record(1)

perf                              2020-01-06                     PERF-SCHED(1)