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| author |   Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-11-20 22:19:44 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2009-11-21 14:11:35 +0100 |
| commit | 0cff784ae41cc125368ae77f1c01328ae2fdc6b3 (patch) | |
| tree | 54e6f387d945d724c00bb33118ef138831a68d10 /kernel/perf_event.c | |
| parent | perf: Allow for custom overflow handlers (diff) | |
| download | linux-dev-0cff784ae41cc125368ae77f1c01328ae2fdc6b3.tar.xz linux-dev-0cff784ae41cc125368ae77f1c01328ae2fdc6b3.zip | |
perf: Optimize some swcounter attr.sample_period==1 paths
Avoid the rather expensive perf_swevent_set_period() if we know
we have to sample every single event anyway.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212508.299508332@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 1dfb6cc4fdea..8e55b440e28a 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3759,16 +3759,16 @@ again: return nr; } -static void perf_swevent_overflow(struct perf_event *event, +static void perf_swevent_overflow(struct perf_event *event, u64 overflow, int nmi, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; int throttle = 0; - u64 overflow; data->period = event->hw.last_period; - overflow = perf_swevent_set_period(event); + if (!overflow) + overflow = perf_swevent_set_period(event); if (hwc->interrupts == MAX_INTERRUPTS) return; @@ -3801,14 +3801,19 @@ static void perf_swevent_add(struct perf_event *event, u64 nr, atomic64_add(nr, &event->count); + if (!regs) + return; + if (!hwc->sample_period) return; - if (!regs) + if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) + return perf_swevent_overflow(event, 1, nmi, data, regs); + + if (atomic64_add_negative(nr, &hwc->period_left)) return; - if (!atomic64_add_negative(nr, &hwc->period_left)) - perf_swevent_overflow(event, nmi, data, regs); + perf_swevent_overflow(event, 0, nmi, data, regs); } static int perf_swevent_is_counting(struct perf_event *event) |