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    SubjectRe: [PATCH][RFC] ftrace: function oprofiler

    On Sat, 25 Oct 2008, Fr?d?ric Weisbecker wrote:

    > Hi Steven,
    >
    > 2008/10/25 Steven Rostedt <rostedt@goodmis.org>:
    > > # cat /debug/tracing/ftrace_profile | sort -brn | head -20
    > > 280075 : __rcu_read_unlock+0xb/0xa2
    > > 280065 : __rcu_read_lock+0x11/0xb3
    >
    > The rcu function are on top of this profile. May be it's because you use
    > rcu when you touch your hash table.
    > Wouldn't be interesting to disable the counter adding for these
    > functions when they
    > are used at this time?

    It is disabled at that time. Look at the trace_active variable. If it
    is already set for that CPU, the counter is disabled.

    But! That said. I need to make the count an atomic inc. There's nothing
    protecting it from SMP.

    >
    > > +config FUNCTION_PROFILER
    > > + bool "Trace max stack"
    >
    > Copy-paste error? :-)

    Hehe, yeah. This and the above bug are both the cause of writing this
    after midnight. That is exactly why I said this is not ready for inclusion
    ;-)

    -- Steve



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