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Commit 984b838c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: Clean up global vs counter enable 



Ingo noticed that both AMD and P6 call
x86_pmu_disable_counter() on *_pmu_enable_counter(). This is
because we rely on the side effect of that call to program
the event config but not touch the EN bit.

We change that for AMD by having enable_all() simply write
the full config in, and for P6 by explicitly coding it.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9c74fb50

arch/x86/kernel/cpu/perf_counter.c

+8 −8
Original line number Diff line number Diff line
@@ -874,13 +874,13 @@ static void amd_pmu_enable_all(void) 
	barrier();



	for (idx = 0; idx < x86_pmu.num_counters; idx++) {

		struct perf_counter *counter = cpuc->counters[idx];

		u64 val;



		if (!test_bit(idx, cpuc->active_mask))

			continue;

		rdmsrl(MSR_K7_EVNTSEL0 + idx, val);

		if (val & ARCH_PERFMON_EVENTSEL0_ENABLE)

			continue;



		val = counter->hw.config;

		val |= ARCH_PERFMON_EVENTSEL0_ENABLE;

		wrmsrl(MSR_K7_EVNTSEL0 + idx, val);

	}
@@ -1044,11 +1044,13 @@ intel_pmu_enable_fixed(struct hw_perf_counter *hwc, int __idx) 
static void p6_pmu_enable_counter(struct hw_perf_counter *hwc, int idx)

{

	struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);

	u64 val;



	val = hwc->config;

	if (cpuc->enabled)

		x86_pmu_enable_counter(hwc, idx);

	else

		x86_pmu_disable_counter(hwc, idx);

		val |= ARCH_PERFMON_EVENTSEL0_ENABLE;



	(void)checking_wrmsrl(hwc->config_base + idx, val);

}
@@ -1068,8 +1070,6 @@ static void amd_pmu_enable_counter(struct hw_perf_counter *hwc, int idx) 


	if (cpuc->enabled)

		x86_pmu_enable_counter(hwc, idx);

	else

		x86_pmu_disable_counter(hwc, idx);

}



static int