Re: [PATCH 4/5] perf, x86: Add INST_RETIRED.ALL workarounds

From: Andi Kleen
Date: Fri Aug 15 2014 - 13:21:39 EST


> So no need to 'fix' the tools, al we need to do is refuse to create
> INST_RETIRED:ALL events with sample_period < 128.

Like this?

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index a0adf58..c592d4d 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -443,6 +443,12 @@ int x86_pmu_hw_config(struct perf_event *event)
if (event->attr.type == PERF_TYPE_RAW)
event->hw.config |= event->attr.config & X86_RAW_EVENT_MASK;

+ if (event->attr.sample_period && x86_pmu.limit_period) {
+ if (x86_pmu.limit_period(event, event->attr.sample_period) <
+ event->attr.sample_period)
+ return -EINVAL;
+ }
+
return x86_setup_perfctr(event);
}

-Andi
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