kernel_optimize_test/tools/perf/Documentation/perf-stat.txt

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perf-stat(1)
============
NAME
----
perf-stat - Run a command and gather performance counter statistics
SYNOPSIS
--------
[verse]
'perf stat' [-e <EVENT> | --event=EVENT] [-S] [-a] <command>
'perf stat' [-e <EVENT> | --event=EVENT] [-S] [-a] -- <command> [<options>]
DESCRIPTION
-----------
This command runs a command and gathers performance counter statistics
from it.
OPTIONS
-------
<command>...::
Any command you can specify in a shell.
-e::
--event=::
Select the PMU event. Selection can be a symbolic event name
(use 'perf list' to list all events) or a raw PMU
event (eventsel+umask) in the form of rNNN where NNN is a
hexadecimal event descriptor.
-i::
--no-inherit::
child tasks do not inherit counters
-p::
--pid=<pid>::
stat events on existing pid
-a::
system-wide collection
-c::
scale counter values
perf stat: add perf stat -B to pretty print large numbers It is hard to read very large numbers so provide an option to perf stat to separate thousands using a separator. The patch leverages the locale support of stdio. You need to set your LC_NUMERIC appropriately, for instance LC_NUMERIC=en_US.UTF8. You need to pass -B to activate this feature. This way existing scripts parsing the output do not need to be changed. Here is an example. $ perf stat noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.347031 task-clock-msecs # 0.998 CPUs 61 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 118 page-faults # 0.000 M/sec 4,138,410,900 cycles # 2070.917 M/sec (scaled from 70.01%) 2,062,650,268 instructions # 0.498 IPC (scaled from 70.01%) 2,057,653,466 branches # 1029.678 M/sec (scaled from 70.01%) 40,267 branch-misses # 0.002 % (scaled from 30.04%) 2,055,961,348 cache-references # 1028.831 M/sec (scaled from 30.03%) 53,725 cache-misses # 0.027 M/sec (scaled from 30.02%) 2.001393933 seconds time elapsed $ perf stat -B noploop 2 noploop for 2 seconds Performance counter stats for 'noploop 2': 1998.297883 task-clock-msecs # 0.998 CPUs 59 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 119 page-faults # 0.000 M/sec 4,131,380,160 cycles # 2067.450 M/sec (scaled from 70.01%) 2,059,096,507 instructions # 0.498 IPC (scaled from 70.01%) 2,054,681,303 branches # 1028.216 M/sec (scaled from 70.01%) 25,650 branch-misses # 0.001 % (scaled from 30.05%) 2,056,283,014 cache-references # 1029.017 M/sec (scaled from 30.03%) 47,097 cache-misses # 0.024 M/sec (scaled from 30.02%) 2.001391016 seconds time elapsed Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4bf28fe8.914ed80a.01ca.fffff5f5@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-18 21:00:01 +08:00
-B::
print large numbers with thousands' separators according to locale
-C::
--cpu=::
Count only on the list of cpus provided. Multiple CPUs can be provided as a
comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
In per-thread mode, this option is ignored. The -a option is still necessary
to activate system-wide monitoring. Default is to count on all CPUs.
EXAMPLES
--------
$ perf stat -- make -j
Performance counter stats for 'make -j':
8117.370256 task clock ticks # 11.281 CPU utilization factor
678 context switches # 0.000 M/sec
133 CPU migrations # 0.000 M/sec
235724 pagefaults # 0.029 M/sec
24821162526 CPU cycles # 3057.784 M/sec
18687303457 instructions # 2302.138 M/sec
172158895 cache references # 21.209 M/sec
27075259 cache misses # 3.335 M/sec
Wall-clock time elapsed: 719.554352 msecs
SEE ALSO
--------
linkperf:perf-top[1], linkperf:perf-list[1]