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For those put off by the baroque interface and daunting learning curve of [[Oprofile]], Ingo Molnár's perf tool (included with the linux kernel since at least version 2.6.30 in <tt>tools/perf</tt>) is a quick and easy way to get data from x86's [[Performance Counters|performance counters]]. | For those put off by the baroque interface and daunting learning curve of [[Oprofile]], Ingo Molnár's perf tool (included with the linux kernel since at least version 2.6.30 in <tt>tools/perf</tt>) is a quick and easy way to get data from x86's [[Performance Counters|performance counters]]. | ||
You need to have <tt>CONFIG_LOCKDEP</tt> and <tt>CONFIG_LOCK_STAT</tt> enabled to use <tt>perf lock</tt>. | |||
==perf stat== | |||
* <tt>-r num</tt> can be used to run the pass <tt>num</tt> times, displaying a standard deviation: | |||
<pre> | |||
Performance counter stats for './notcurses-demo -k -c ww' (3 runs): | |||
23,153,745,413 cycles ( +- 0.64% ) | |||
67,109,369,279 instructions # 2.90 insn per cycle ( +- 0.35% ) | |||
86,574,323 cache-misses ( +- 1.79% ) | |||
10,555,354,499 branches ( +- 0.35% ) | |||
11.0698 +- 0.0119 seconds time elapsed ( +- 0.11% ) | |||
</pre> | |||
==See Also== | ==See Also== | ||
* 2009-06-06 [http://lkml.org/lkml/2009/6/6/149 LKML post] announcing version -v8 | * 2009-06-06 [http://lkml.org/lkml/2009/6/6/149 LKML post] announcing version -v8 | ||