From dbc33f7016747bfce64f3d1e3af63f1251fcbf85 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Mon, 9 Sep 2013 12:53:50 -0700 Subject: perf/x86: Fix uncore PCI fixed counter handling There was a bug in the handling of SNB-EP/IVB-EP uncore PCI fixed counters, e.g., IMC. It would cause erratic values to be returned for the IMC clockticks event. This was due to a bogus hwc->config value which was then written to PCI config space. The erratic values can be seen via: $ perf stat -a -C 0 -e uncore_imc_0/clockticks/ -I 1000 sleep 10 The fixed counter has most fields marked as reserved with hw reset values of 0. Yet the kernel was defaulting to a hwc->config = ~0 and that was causing the issues. This patch sets the hwc->config values for fixed uncore event to 0. Now, the values of IMC clockticks is correct. Signed-off-by: Stephane Eranian Reviewed-by: Andi Kleen Cc: peterz@infradead.org Cc: zheng.z.yan@intel.com Link: http://lkml.kernel.org/r/20130909195350.GA17643@google.com Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c index fd8011e..8ed4458 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c @@ -2808,7 +2808,7 @@ uncore_get_event_constraint(struct intel_uncore_box *box, struct perf_event *eve return c; } - if (event->hw.config == ~0ULL) + if (event->attr.config == UNCORE_FIXED_EVENT) return &constraint_fixed; if (type->constraints) { @@ -3112,7 +3112,9 @@ static int uncore_pmu_event_init(struct perf_event *event) */ if (pmu->type->single_fixed && pmu->pmu_idx > 0) return -EINVAL; - hwc->config = ~0ULL; + + /* fixed counters have event field hardcoded to zero */ + hwc->config = 0ULL; } else { hwc->config = event->attr.config & pmu->type->event_mask; if (pmu->type->ops->hw_config) { -- cgit v0.10.2