Commit 32975a4f authored Mar 06, 2010 by Peter Zijlstra Committed by Ingo Molnar Mar 10, 2010

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>

parent 3f6da390

kernel/perf_event.c

+3 −13

Original line number	Diff line number	Diff line
		@@ -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();
		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();
		}