2e6cdf996b
By default, event inheritance across fork and pthread_create was on but the -i option of stat and record, which enabled inheritance, led to believe it was off by default. This patch fixes this logic by inverting the meaning of the -i option. By default inheritance is on whether you attach to a process (-p), a thread (-t) or start a process. If you pass -i, then you turn off inheritance. Turning off inheritance if you don't need it, helps limit perf resource usage as well. The patch also fixes perf stat -t xxxx and perf record -t xxxx which did not start the counters. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <4bea9d2f.d60ce30a.0b5b.08e1@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
67 lines
1.5 KiB
Plaintext
67 lines
1.5 KiB
Plaintext
perf-stat(1)
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============
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NAME
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----
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perf-stat - Run a command and gather performance counter statistics
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SYNOPSIS
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--------
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[verse]
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'perf stat' [-e <EVENT> | --event=EVENT] [-S] [-a] <command>
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'perf stat' [-e <EVENT> | --event=EVENT] [-S] [-a] -- <command> [<options>]
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DESCRIPTION
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-----------
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This command runs a command and gathers performance counter statistics
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from it.
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OPTIONS
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-------
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<command>...::
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Any command you can specify in a shell.
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-e::
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--event=::
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Select the PMU event. Selection can be a symbolic event name
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(use 'perf list' to list all events) or a raw PMU
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event (eventsel+umask) in the form of rNNN where NNN is a
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hexadecimal event descriptor.
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-i::
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--no-inherit::
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child tasks do not inherit counters
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-p::
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--pid=<pid>::
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stat events on existing pid
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-a::
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system-wide collection
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-c::
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scale counter values
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EXAMPLES
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--------
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$ perf stat -- make -j
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Performance counter stats for 'make -j':
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8117.370256 task clock ticks # 11.281 CPU utilization factor
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678 context switches # 0.000 M/sec
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133 CPU migrations # 0.000 M/sec
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235724 pagefaults # 0.029 M/sec
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24821162526 CPU cycles # 3057.784 M/sec
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18687303457 instructions # 2302.138 M/sec
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172158895 cache references # 21.209 M/sec
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27075259 cache misses # 3.335 M/sec
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Wall-clock time elapsed: 719.554352 msecs
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SEE ALSO
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--------
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linkperf:perf-top[1], linkperf:perf-list[1]
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