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Perf

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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 tools/perf) is a quick and easy way to get data from x86's performance counters.

You need to have CONFIG_LOCKDEP and CONFIG_LOCK_STAT enabled to use perf lock.

perf stat

  • -r num can be used to run the pass num times, displaying a standard deviation:
 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% )

See Also