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    SubjectRe: perf_counters issue with enable_on_exec
    Peter Zijlstra writes:

    > 2. enable_on_exec only works on leaders, Paul, was that intended?

    I think I thought that would be sufficient, but I guess it would be
    cleaner if it also worked on non-leaders.

    > 3. the scale stuff seems broken
    >
    > # perf stat -e cycles -e instructions --repeat 10 true
    >
    > Performance counter stats for 'true' (10 runs):
    >
    > 2612124 cycles ( +- 1.327% )
    > 1870479 instructions # 0.716 IPC ( +- 0.132% )
    >
    > 0.003743155 seconds time elapsed ( +- 1.203% )
    >
    > # ./test-enable_on_exec true
    > 2651600 PERF_COUNT_HW_CPU_CYCLES 1111509 1111509 2651600.000000
    > 1832720 PERF_COUNT_HW_INSTRUCTIONS 839395242 1111509 1384043177.264637
    >
    > Paul, would a counter's time start running when its 'enabled' but part
    > of a non-runnable group?

    No, it shouldn't. If it does it's a bug.

    Paul.


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