Re: [PATCH -v3] perf, x86: try to handle unknown nmis with runningperfctrs

[Peter Zijlstra]

On Fri, 2010-08-27 at 09:57 +0200, Robert Richter wrote:
> On 26.08.10 14:02:50, Cyrill Gorcunov wrote:
> > > diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
> > > index 4539b4b..9e65a7b 100644
> > > --- a/arch/x86/kernel/cpu/perf_event_intel.c
> > > +++ b/arch/x86/kernel/cpu/perf_event_intel.c
> > > @@ -777,7 +777,9 @@ again:
> > >  
> > >  done:
> > >  	intel_pmu_enable_all(0);
> > > -	return handled;
> > > +	if (!handled)
> > > +		return handled;
> > > +	return ++handled;
> > >  }
> > >  
> > >  static struct event_constraint *
> > > 
> > 
> > ok, it seems it just treat any unknown nmi as being came from PMU, no?
> 
> Yes, this just throws away all unknown nmis after a perf nmi. It
> disables unknown nmi detection on this cpu type.

Wouldn't returning 2 be more sensible, then it would only eat a few
unknowns after each pmi? (Still assuming you return 0 when there really
was nothing to do)
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