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perf: Optimize perf_disable 

Currently we always call hw_perf_disable(), even if its already disabled,
this seems superflous, esp. since it cannot be made NMI safe (see further
patches).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-03-06 19:49:19 +01:00 committed by Ingo Molnar
parent 3f6da39053
commit 32975a4f11
1 changed files with 3 additions and 13 deletions
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16
kernel/perf_event.c
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@ -93,25 +93,15 @@ void __weak perf_event_print_debug(void) { }
static DEFINE_PER_CPU(int, perf_disable_count);
void __perf_disable(void)
{
__get_cpu_var(perf_disable_count)++;
}
bool __perf_enable(void)
{
return !--__get_cpu_var(perf_disable_count);
}
void perf_disable(void)
{
__perf_disable();
hw_perf_disable();
if (!__get_cpu_var(perf_disable_count)++)
hw_perf_disable();
}
void perf_enable(void)
{
if (__perf_enable())
if (!--__get_cpu_var(perf_disable_count))
hw_perf_enable();
}