Messages in this thread | | | Date | Thu, 15 Aug 2013 13:49:32 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 1/2] perf x86: Make intel_pmu_enable_all to enable only active events |
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On Thu, Aug 15, 2013 at 01:40:40PM +0200, Peter Zijlstra wrote: > 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.
hum, I might have misread the doc.. strange the test showed this result
jirka
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