diff options
| author | Stephane Eranian <eranian@google.com> | 2012-02-02 12:04:01 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2012-02-03 08:24:40 +0100 |
| commit | 84f2b9b2edc09595569c7397cc3c888764ffd78b (patch) | |
| tree | f959f7f5746b3dc8409b2aae9584101c9b2f71a1 /arch/x86/kernel/cpu/perf_event_intel_lbr.c | |
| parent | 6c073a7ee250118b8be3a2379c96fd7f78382b06 (diff) | |
perf: Remove deprecated WARN_ON_ONCE()
With the new throttling/unthrottling code introduced with
commit:
e050e3f0a71b ("perf: Fix broken interrupt rate throttling")
we occasionally hit two WARN_ON_ONCE() checks in:
- intel_pmu_pebs_enable()
- intel_pmu_lbr_enable()
- x86_pmu_start()
The assertions are no longer problematic. There is a valid
path where they can trigger but it is harmless.
The assertion can be triggered with:
$ perf record -e instructions:pp ....
Leading to paths:
intel_pmu_pebs_enable
intel_pmu_enable_event
x86_perf_event_set_period
x86_pmu_start
perf_adjust_freq_unthr_context
perf_event_task_tick
scheduler_tick
And:
intel_pmu_lbr_enable
intel_pmu_enable_event
x86_perf_event_set_period
x86_pmu_start
perf_adjust_freq_unthr_context.
perf_event_task_tick
scheduler_tick
cpuc->enabled is always on because when we get to
perf_adjust_freq_unthr_context() the PMU is not totally
disabled. Furthermore when we need to adjust a period,
we only stop the event we need to change and not the
entire PMU. Thus, when we re-enable, cpuc->enabled is
already set. Note that when we stop the event, both
pebs and lbr are stopped if necessary (and possible).
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/20120202110401.GA30911@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_lbr.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_lbr.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index 3fab3de3ce9..47a7e63bfe5 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -72,8 +72,6 @@ void intel_pmu_lbr_enable(struct perf_event *event) if (!x86_pmu.lbr_nr) return; - WARN_ON_ONCE(cpuc->enabled); - /* * Reset the LBR stack if we changed task context to * avoid data leaks. |