Messages in this thread | | | Date | Wed, 29 Sep 2010 17:33:07 +0200 | Subject | Re: [tip:perf/urgent] perf, x86: Catch spurious interrupts after disabling counters | From | Stephane Eranian <> |
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Robert,
There is something else bothering me with cpuc->running.
It is not reset outside of the interrupt handler. So what if event scheduling shuffles things around and an event is moved somewhere else. Don't you need to clear the cpuc->running[idx] for the old counter index?
On Wed, Sep 29, 2010 at 5:27 PM, Cyrill Gorcunov <gorcunov@gmail.com> wrote: > On Wed, Sep 29, 2010 at 05:12:53PM +0200, Robert Richter wrote: >> On 29.09.10 17:01:40, Robert Richter wrote: >> > Right, I wasn't remembering correctly, it was P6 and core. And yes, P4 >> > requires the fix. Will send a patch for this. >> >> Ok, Cyrill is sending the patch. >> >> Thanks, >> >> -Robert >> > > Managed to implement it earlier then I thought. > > Cyrill > --- > Subject: [PATCH -tip] perf, x86: Handle in flight IRQs on P4 platform > > Stephane reported we've missed to guard P4 platform > against spurious in-flight performance IRQs. Fix it. > > [ the patch is a complement to commit 63e6be6d98e1 ] > > Reported-by: Stephane Eranian <eranian@google.com> > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > CC: Robert Richter <robert.richter@amd.com> > CC: Lin Ming <ming.m.lin@intel.com> > --- > arch/x86/kernel/cpu/perf_event_p4.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c > ===================================================================== > --- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event_p4.c > +++ linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c > @@ -904,8 +904,12 @@ static int p4_pmu_handle_irq(struct pt_r > for (idx = 0; idx < x86_pmu.num_counters; idx++) { > int overflow; > > - if (!test_bit(idx, cpuc->active_mask)) > + if (!test_bit(idx, cpuc->active_mask)) { > + /* catch in-flight IRQs */ > + if (__test_and_clear_bit(idx, cpuc->running)) > + handled++; > continue; > + } > > event = cpuc->events[idx]; > hwc = &event->hw; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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