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    SubjectRe: [RFC][PATCH 1/2 v2] tracing: Add TRACE_EVENT_CONDITIONAL()
    * Steven Rostedt (rostedt@goodmis.org) wrote:
    > On Fri, 2010-12-03 at 10:27 -0500, Mathieu Desnoyers wrote:
    >
    > > > > TP_CONDITION(unlikely(someparam)),
    > > >
    > > > I actually think this is an abuse of "unlikely".
    > >
    > > Why are you considering this an abuse ?
    >
    > Because it is overused. I would rather get rid of most unlikely()'s
    > because they are mostly meaningless. Just run the unlikely profiler, and
    > you will see a large number of them are just plain incorrect.
    >
    > Adding them here probably doesn't do any good. The only reason for this
    > TP_CONDITION() is to ignore those cases that it just does not make sense
    > to trace. Like a wake up tracepoint that does not wake anything up. No
    > need for "unlikely" or "likely", by trying to do that, you will most
    > likely get it wrong.
    >
    > unlikely(use_likely_correctly)

    Ah OK. You are afraid that people will misuse it, not saying that it would be
    technically incorrect. Fair enough. It sounds like a good enough reason for not
    documenting this use-case.

    Thanks,

    Mathieu

    --
    Mathieu Desnoyers
    Operating System Efficiency R&D Consultant
    EfficiOS Inc.
    http://www.efficios.com


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