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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)
perf-sched - Tool to trace/measure scheduler properties (latencies)
perf sched {record|latency|map|replay|script|timehist}
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.
-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.
--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.
-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.
perf-record(1)
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)