Messages in this thread Patch in this message | | | Subject | Re: [PATCH 3/4] perf_counter: frequency based adaptive irq_period | From | Peter Zijlstra <> | Date | Fri, 15 May 2009 15:37:47 +0200 |
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On Fri, 2009-05-15 at 15:19 +0200, Peter Zijlstra wrote: > plain text document attachment (perf_counter-freq.patch) > Instead of specifying the irq_period for a counter, provide a target interrupt > frequency and dynamically adapt the irq_period to match this frequency. > > Paul, please verify ppc64, I only did a very quick pass over that code. > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > CC: Paul Mackerras <paulus@samba.org> > CC: Corey Ashford <cjashfor@linux.vnet.ibm.com> > ---
> @@ -2907,6 +2940,12 @@ perf_counter_alloc(struct perf_counter_h > > pmu = NULL; > > + hwc = &counter->hw; > + if (hw_event->freq && hw_event->irq_freq) > + hwc->irq_period = TICK_NSEC / hw_event->irq_freq; > + else > + hwc->irq_period = hw_event->irq_period; > +
kernel/built-in.o: In function `perf_counter_alloc': perf_counter.c:(.text+0x7ddc7): undefined reference to `__udivdi3'
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> ---
Index: linux-2.6/kernel/perf_counter.c =================================================================== --- linux-2.6.orig/kernel/perf_counter.c +++ linux-2.6/kernel/perf_counter.c @@ -2942,7 +2942,7 @@ perf_counter_alloc(struct perf_counter_h hwc = &counter->hw; if (hw_event->freq && hw_event->irq_freq) - hwc->irq_period = TICK_NSEC / hw_event->irq_freq; + hwc->irq_period = div64_u64(TICK_NSEC, hw_event->irq_freq); else hwc->irq_period = hw_event->irq_period;
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