Messages in this thread | | | Subject | Re: register_timer_hook use in arch/sh/oprofile | From | Peter Zijlstra <> | Date | Fri, 26 Jun 2009 09:36:32 +0200 |
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On Fri, 2009-06-26 at 09:23 +0200, Ingo Molnar wrote: > * Peter Zijlstra <peterz@infradead.org> wrote: > > > On Wed, 2009-06-24 at 15:24 +0200, Ingo Molnar wrote: > > > > > > [ And long-term analysis ('perf stat' type of runs) dont need IRQs > > > anyway - perfcounters reads outs the counts and summarizes them > > > across the measured workload. ] > > > > If the counter width is less than 64 bits we do need to have some > > interrupt to read them from before they cycle so we can accumulate > > the deltas into a proper u64. > > Yeah - but even that can be driven from some housekeeping hrtimer.
Oh absolutely, but its one of those things one should not forget to do.
> > But for proper 64 bit hardware counters there is indeed no need > > for that. > > Indeed - although they are rare.
Paul Mundt mentioned he had some.
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