From 8882edf735738c949aba4b65d3ec3453066bab12 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 27 Feb 2015 09:48:30 -0800 Subject: [PATCH] perf/x86/intel: Reset more state in PMU reset The PMU reset code didn't quite keep up with newer PMU features. Improve it a bit to really reset a modern PMU: - Clear all overflow status - Clear LBRs and freezing state - Disable fixed counters too Signed-off-by: Andi Kleen Signed-off-by: Peter Zijlstra (Intel) Cc: eranian@google.com Link: http://lkml.kernel.org/r/1425059312-18217-2-git-send-email-andi@firstfloor.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_intel.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 6ea61a5..5999460 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1538,6 +1538,18 @@ static void intel_pmu_reset(void) if (ds) ds->bts_index = ds->bts_buffer_base; + /* Ack all overflows and disable fixed counters */ + if (x86_pmu.version >= 2) { + intel_pmu_ack_status(intel_pmu_get_status()); + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0); + } + + /* Reset LBRs and LBR freezing */ + if (x86_pmu.lbr_nr) { + update_debugctlmsr(get_debugctlmsr() & + ~(DEBUGCTLMSR_FREEZE_LBRS_ON_PMI|DEBUGCTLMSR_LBR)); + } + local_irq_restore(flags); } -- 2.7.4