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perf: Convert perf_event to local_t

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Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2010-05-21 14:43:08 +02:00
committed by Ingo Molnar
parent a6e6dea68c
commit e78505958c
7 changed files with 72 additions and 71 deletions
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6
arch/sh/kernel/perf_event.c
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@ -185,10 +185,10 @@ static void sh_perf_event_update(struct perf_event *event,
* this is the simplest approach for maintaining consistency.
*/
again:
prev_raw_count = atomic64_read(&hwc->prev_count);
prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = sh_pmu->read(idx);
if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count)
goto again;
@ -203,7 +203,7 @@ again:
delta = (new_raw_count << shift) - (prev_raw_count << shift);
delta >>= shift;
atomic64_add(delta, &event->count);
local64_add(delta, &event->count);
}
static void sh_pmu_disable(struct perf_event *event)