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Commit a6e6dea6 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf: Add perf_event::child_count 



Only child counters adding back their values into the parent counter
are responsible for cross-cpu updates to event->count.

So if we pull that out into a new child_count variable, we get an
event->count that is only modified locally.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b5e58793

include/linux/perf_event.h

+1 −0
Original line number Diff line number Diff line
@@ -671,6 +671,7 @@ struct perf_event { 
	enum perf_event_active_state	state;

	unsigned int			attach_state;

	atomic64_t			count;

	atomic64_t			child_count;



	/*

	 * These are the total time in nanoseconds that the event

kernel/perf_event.c

+2 −2
Original line number Diff line number Diff line
@@ -1738,7 +1738,7 @@ static void __perf_event_read(void *info) 


static inline u64 perf_event_count(struct perf_event *event)

{

	return atomic64_read(&event->count);

	return atomic64_read(&event->count) + atomic64_read(&event->child_count);

}



static u64 perf_event_read(struct perf_event *event)
@@ -5379,7 +5379,7 @@ static void sync_child_event(struct perf_event *child_event, 
	/*

	 * Add back the child's count to the parent's count:

	 */

	atomic64_add(child_val, &parent_event->count);

	atomic64_add(child_val, &parent_event->child_count);

	atomic64_add(child_event->total_time_enabled,

		     &parent_event->child_total_time_enabled);

	atomic64_add(child_event->total_time_running,