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: Peter 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: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index ab4c0ff..a395fda 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1738,7 +1738,7 @@
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 @@
/*
* 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,
