Messages in this thread | | | Date | Thu, 12 Feb 2009 23:18:56 -0500 (EST) | From | Steven Rostedt <> | Subject | Re: [PATCH 2/7][RFC] powerpc64: port of the function graph tracer |
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On Fri, 13 Feb 2009, Benjamin Herrenschmidt wrote:
> > On Wed, 2009-02-11 at 20:10 -0500, Steven Rostedt wrote: > > > > +# timers used by tracing > > +CFLAGS_REMOVE_time.o = -pg -mno-sched-epilog > > endif > > That means no tracing of the timer interrupts etc... maybe we should > just move the specific function that we don't want traced out to a > separate file ?
The function graph tracer calls cpu_clock, which calls sched_clock, to get the times. There's no protection against recursion here, since we want to let interrupts still be recorded, and we do not need to disable interrupts.
But if the cpu_clock calls something that is traced, it will recurse, and cause a lockup. What ever functions those are, we could annotate with notrace. I just used the x86 blind method of 'dont trace this file'.
> > Appart from that, it looks ok, though I might have missed something :-)
Thanks,
-- Steve
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