Re: [PATCH 3/4] perf/x86/intel/ds: Handle PEBS overflow for fixed counters

From: Peter Zijlstra
Date: Mon Jul 23 2018 - 12:21:21 EST


On Mon, Jul 23, 2018 at 04:59:44PM +0200, Peter Zijlstra wrote:
> On Thu, Mar 08, 2018 at 06:15:41PM -0800, kan.liang@xxxxxxxxxxxxxxx wrote:
> > diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> > index ef47a418d819..86149b87cce8 100644
> > --- a/arch/x86/events/intel/core.c
> > +++ b/arch/x86/events/intel/core.c
> > @@ -2280,7 +2280,10 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
> > * counters from the GLOBAL_STATUS mask and we always process PEBS
> > * events via drain_pebs().
> > */
> > - status &= ~(cpuc->pebs_enabled & PEBS_COUNTER_MASK);
> > + if (x86_pmu.flags & PMU_FL_PEBS_ALL)
> > + status &= ~(cpuc->pebs_enabled & EXTENDED_PEBS_COUNTER_MASK);
> > + else
> > + status &= ~(cpuc->pebs_enabled & PEBS_COUNTER_MASK);
> >
> > /*
> > * PEBS overflow sets bit 62 in the global status register
>
> Doesn't this re-introduce the problem fixed in commit fd583ad1563be,
> where pebs_enabled:32-34 are PEBS Load Latency, instead of fixed
> counters?

Also, since they 'fixed' that conflict, the PEBS_ALL version could be:

state &= cpuc->pebs_enabled;

Right?