diff options
| author |   Stephane Eranian <eranian@google.com> | 2013-09-09 12:53:50 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2013-09-12 08:42:37 +0200 |
| commit | dbc33f7016747bfce64f3d1e3af63f1251fcbf85 (patch) | |
| tree | 8523036d438767c26acd85da2b083861730b9537 | |
| parent | uprobes: Fix utask->depth accounting in handle_trampoline() (diff) | |
| download | linux-dev-dbc33f7016747bfce64f3d1e3af63f1251fcbf85.tar.xz linux-dev-dbc33f7016747bfce64f3d1e3af63f1251fcbf85.zip | |
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 <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
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 <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_uncore.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c index fd8011ed4dcd..8ed44589b0e4 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) { |