Commit 151ee834 authored Dec 11, 2015 by Namhyung Kim Committed by Arnaldo Carvalho de Melo Dec 11, 2015

perf top: Access hists->lock only if needed

The perf_top__record_precise_ip() releases and regrabs the
he->hists->lock because it can sleep if there's an error.  But it should
be done conditionally as it slows down the fast path.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1449802616-16170-2-git-send-email-namhyung@kernel.org

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 64226bcf

tools/perf/builtin-top.c

+15 −13

Original line number	Diff line number	Diff line
		@@ -194,6 +194,7 @@ static void perf_top__record_precise_ip(struct perf_top *top,

		pthread_mutex_unlock(&notes->lock);

		if (unlikely(err)) {
		/*
		* This function is now called with he->hists->lock held.
		* Release it before going to sleep.
		@@ -210,6 +211,7 @@ static void perf_top__record_precise_ip(struct perf_top *top,

		pthread_mutex_lock(&he->hists->lock);
		}
		}

		static void perf_top__show_details(struct perf_top *top)
		{