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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-18 20:14:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-18 20:47:30 +0200 |
| commit | def0a9b2573e00ab0b486cb5382625203ab4c4a6 (patch) | |
| tree | 1e3086fc320c244297b5b63cce47065bcfb71e8c /kernel/perf_counter.c | |
| parent | cf450a7355a116af793998c118a6bcf7f5a8367e (diff) | |
| download | kernel_samsung_smdk4412-def0a9b2573e00ab0b486cb5382625203ab4c4a6.zip kernel_samsung_smdk4412-def0a9b2573e00ab0b486cb5382625203ab4c4a6.tar.gz kernel_samsung_smdk4412-def0a9b2573e00ab0b486cb5382625203ab4c4a6.tar.bz2 | |
sched_clock: Make it NMI safe
Arjan complained about the suckyness of TSC on modern machines, and
asked if we could do something about that for PERF_SAMPLE_TIME.
Make cpu_clock() NMI safe by removing the spinlock and using
cmpxchg. This also makes it smaller and more robust.
Affects architectures that use HAVE_UNSTABLE_SCHED_CLOCK, i.e. IA64
and x86.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/perf_counter.c')
| -rw-r--r-- | kernel/perf_counter.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 6944bd5..06d233a 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -2955,10 +2955,7 @@ void perf_prepare_sample(struct perf_event_header *header, } if (sample_type & PERF_SAMPLE_TIME) { - /* - * Maybe do better on x86 and provide cpu_clock_nmi() - */ - data->time = sched_clock(); + data->time = perf_clock(); header->size += sizeof(data->time); } @@ -3488,7 +3485,7 @@ static void perf_log_throttle(struct perf_counter *counter, int enable) .misc = 0, .size = sizeof(throttle_event), }, - .time = sched_clock(), + .time = perf_clock(), .id = primary_counter_id(counter), .stream_id = counter->id, }; @@ -3540,7 +3537,7 @@ static int __perf_counter_overflow(struct perf_counter *counter, int nmi, } if (counter->attr.freq) { - u64 now = sched_clock(); + u64 now = perf_clock(); s64 delta = now - hwc->freq_stamp; hwc->freq_stamp = now; |