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perf: Optimize the perf_output() path by removing IRQ-disables

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Since we can now assume there is only a single writer
to each buffer, we can remove per-cpu lock thingy and
use a simply nest-count to the same effect.

This removes the need to disable IRQs.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-05-18 10:50:41 +02:00 • committed by Ingo Molnar
parent c7920614ce
commit ef60777c9a
2 changed files with 30 additions and 69 deletions
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5
include/linux/perf_event.h
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@ -597,12 +597,12 @@ struct perf_mmap_data {
atomic_t events; /* event_id limit */
atomic_long_t head; /* write position */
atomic_long_t done_head; /* completed head */
atomic_t lock; /* concurrent writes */
atomic_t wakeup; /* needs a wakeup */
atomic_t lost; /* nr records lost */
atomic_t nest; /* nested writers */
long watermark; /* wakeup watermark */
struct perf_event_mmap_page *user_page;
@ -807,7 +807,6 @@ struct perf_output_handle {
unsigned long offset;
int nmi;
int sample;
int locked;
};
#ifdef CONFIG_PERF_EVENTS