Messages in this thread | | | Date | Thu, 15 Aug 2013 13:40:40 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/2] perf x86: Make intel_pmu_enable_all to enable only active events |
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On Tue, Aug 13, 2013 at 06:39:11PM +0200, Jiri Olsa wrote: > Currently the intel_pmu_enable_all enables all possible > events, which is not allways desired. One case (there'll > be probably more) is: > > - event hits throttling threshold > - NMI stops event > - intel_pmu_enable_all starts it back on the NMI exit >
> +++ b/arch/x86/kernel/cpu/perf_event_intel.c > @@ -912,11 +912,13 @@ static void intel_pmu_disable_all(void) > static void intel_pmu_enable_all(int added) > { > struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); > + u64 active_mask = *((u64*) cpuc->active_mask); > > intel_pmu_pebs_enable_all(); > intel_pmu_lbr_enable_all(); > wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, > - x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_guest_mask); > + x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_guest_mask > + & active_mask);
Garh.. you made my head hurt :-)
I think its a NOP; this is the global ctrl register but intel_pmu_disable_event() writes PERFEVTSELx.EN = 0, so even if you enable it in the global mask, the event should still be disabled.
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