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    SubjectRe: [RFC] perf: perf record sets inherit by default
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    On Tue, May 11, 2010 at 5:13 PM, Peter Zijlstra <peterz@infradead.org> wrote:
    > On Tue, 2010-05-11 at 12:00 -0300, Arnaldo Carvalho de Melo wrote:
    >>
    >> Humm, since for -C and -a using -i doesn't make sense, I guess it should
    >> be off by default and only be auto-activated if we don't specify any
    >> option, i.e. when using it like:
    >>
    >> perf record ./hackbench
    >>
    >> What do you think?
    >
    > -ENOPARSE
    >
    > -a/-C usage creates per-cpu counters and will thus ignore any and all
    > perf_event_attr::inherit state.
    >
    > Your above suggestion would still have inherit enabled by default, and
    > would thus not change anything.
    >
    > The thing is that perf-record defaults to inherited per-task-per-cpu
    > counters, which, I think, is a reasonable default, just sub-optimal for
    > single threaded/!forking subjects.
    >
    > So what would make sense is for -i to mean --no-inherit, and for !
    > inherit create a per-task counter instead of a per-task-per-cpu counter.
    >

    If inherit is the preferred default, then yes, the solution is to revert
    the meaning of -i. You'd have to be consistent across all commands
    using -i for inherit such as perf stat.


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