Messages in this thread Patch in this message | | | Date | Tue, 18 Jul 2017 11:14:44 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf/x86/intel: Add proper condition to run sched_task callbacks |
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On Mon, Jul 17, 2017 at 05:01:56PM +0200, Jiri Olsa wrote: > The x86 pmu currently uses the sched_task callback for 2 functions: > - PEBS drain > - save/restore LBR data > > They are both triggered once the x86 pmu is registered with > perf_sched_cb_inc call (within pmu::add callback), regardless > if there's actually any PEBS or LBR event configured on the cpu.
I don't understand. If we do pmu::add() we _are_ on the CPU.
So you're saying intel_pmu_pebs_{add,del}() are doing it wrong? So why not fix those?
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c > index aa62437d1aa1..1f66356d8122 100644 > --- a/arch/x86/events/intel/core.c > +++ b/arch/x86/events/intel/core.c > @@ -3265,9 +3265,11 @@ static void intel_pmu_cpu_dying(int cpu) > static void intel_pmu_sched_task(struct perf_event_context *ctx, > bool sched_in) > { > - if (x86_pmu.pebs_active) > + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); > + > + if (intel_pmu_pebs_needs_sched_cb(cpuc)) > intel_pmu_pebs_sched_task(ctx, sched_in);
So I'm confused, if we'd not need this, how come we're here in the first place?
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