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>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 73329de..d810846 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -93,25 +93,15 @@
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();
}