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Commit 01add3ea authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by Ingo Molnar
Browse files

perf/core: Split perf_event_read() and perf_event_count() 



perf_event_read() does two things:

	- call the PMU to read/update the counter value, and
	- compute the total count of the event and its children

Not all callers need both. perf_event_reset() for instance needs the
first piece but doesn't need the second.  Similarly, when we implement
the ability to read a group of events using the transaction interface,
we would need the two pieces done independently.

Break up perf_event_read() and have it just read/update the counter
and have the callers compute the total count if necessary.

Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-4-git-send-email-sukadev@linux.vnet.ibm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent fbbe0701

kernel/events/core.c

+8 −6
Original line number Original line Diff line number Diff line
@@ -3275,7 +3275,7 @@ u64 perf_event_read_local(struct perf_event *event) 
	return val;

	return val;

}

}





static u64 perf_event_read(struct perf_event *event)

static void perf_event_read(struct perf_event *event)

{

{

	/*

	/*

	 * If event is enabled and currently active on a CPU, update the

	 * If event is enabled and currently active on a CPU, update the
@@ -3301,8 +3301,6 @@ static u64 perf_event_read(struct perf_event *event) 
		update_event_times(event);

		update_event_times(event);

		raw_spin_unlock_irqrestore(&ctx->lock, flags);

		raw_spin_unlock_irqrestore(&ctx->lock, flags);

	}

	}



	return perf_event_count(event);

}

}





/*

/*
@@ -3818,14 +3816,18 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 
	*running = 0;

	*running = 0;





	mutex_lock(&event->child_mutex);

	mutex_lock(&event->child_mutex);

	total += perf_event_read(event);



	perf_event_read(event);

	total += perf_event_count(event);



	*enabled += event->total_time_enabled +

	*enabled += event->total_time_enabled +

			atomic64_read(&event->child_total_time_enabled);

			atomic64_read(&event->child_total_time_enabled);

	*running += event->total_time_running +

	*running += event->total_time_running +

			atomic64_read(&event->child_total_time_running);

			atomic64_read(&event->child_total_time_running);





	list_for_each_entry(child, &event->child_list, child_list) {

	list_for_each_entry(child, &event->child_list, child_list) {

		total += perf_event_read(child);

		perf_event_read(child);

		total += perf_event_count(child);

		*enabled += child->total_time_enabled;

		*enabled += child->total_time_enabled;

		*running += child->total_time_running;

		*running += child->total_time_running;

	}

	}
@@ -3985,7 +3987,7 @@ static unsigned int perf_poll(struct file *file, poll_table *wait) 




static void _perf_event_reset(struct perf_event *event)

static void _perf_event_reset(struct perf_event *event)

{

{

	(void)perf_event_read(event);

	perf_event_read(event);

	local64_set(&event->count, 0);

	local64_set(&event->count, 0);

	perf_event_update_userpage(event);

	perf_event_update_userpage(event);

}

}