From 1c250d709fdc8aa5bf42d90be99428a01a256a55 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Thu, 5 Aug 2010 19:09:17 +0400 Subject: [PATCH] perf, x86: P4 PMU -- update nmi irq statistics and unmask lvt entry properly In case if last active performance counter is not overflowed at moment of NMI being triggered by another counter, the irq statistics may miss an update stage. As a more serious consequence -- apic quirk may not be triggered so apic lvt entry stay masked. Tested-by: Lin Ming Signed-off-by: Cyrill Gorcunov Cc: Stephane Eranian Cc: Peter Zijlstra Cc: Frederic Weisbecker LKML-Reference: <20100805150917.GA6311@lenovo> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_p4.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c index 107711b..febb12c 100644 --- a/arch/x86/kernel/cpu/perf_event_p4.c +++ b/arch/x86/kernel/cpu/perf_event_p4.c @@ -656,6 +656,7 @@ static int p4_pmu_handle_irq(struct pt_regs *regs) cpuc = &__get_cpu_var(cpu_hw_events); for (idx = 0; idx < x86_pmu.num_counters; idx++) { + int overflow; if (!test_bit(idx, cpuc->active_mask)) continue; @@ -666,12 +667,14 @@ static int p4_pmu_handle_irq(struct pt_regs *regs) WARN_ON_ONCE(hwc->idx != idx); /* it might be unflagged overflow */ - handled = p4_pmu_clear_cccr_ovf(hwc); + overflow = p4_pmu_clear_cccr_ovf(hwc); val = x86_perf_event_update(event); - if (!handled && (val & (1ULL << (x86_pmu.cntval_bits - 1)))) + if (!overflow && (val & (1ULL << (x86_pmu.cntval_bits - 1)))) continue; + handled += overflow; + /* event overflow for sure */ data.period = event->hw.last_period; @@ -687,7 +690,7 @@ static int p4_pmu_handle_irq(struct pt_regs *regs) inc_irq_stat(apic_perf_irqs); } - return handled; + return handled > 0; } /* -- 2.7.4