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Commit 0492d4c5 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf/core: Add group reads to perf_event_read() 



Enable perf_event_read() to update entire groups at once, this will be
useful for read transactions.

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: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20150723080435.GE25159@twins.programming.kicks-ass.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b15f495b

kernel/events/core.c

+32 −7
Original line number Diff line number Diff line
@@ -3184,12 +3184,18 @@ void perf_event_exec(void) 
	rcu_read_unlock();

}



struct perf_read_data {

	struct perf_event *event;

	bool group;

};



/*

 * Cross CPU call to read the hardware event

 */

static void __perf_event_read(void *info)

{

	struct perf_event *event = info;

	struct perf_read_data *data = info;

	struct perf_event *sub, *event = data->event;

	struct perf_event_context *ctx = event->ctx;

	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
@@ -3208,9 +3214,21 @@ static void __perf_event_read(void *info) 
		update_context_time(ctx);

		update_cgrp_time_from_event(event);

	}



	update_event_times(event);

	if (event->state == PERF_EVENT_STATE_ACTIVE)

		event->pmu->read(event);



	if (!data->group)

		goto unlock;



	list_for_each_entry(sub, &event->sibling_list, group_entry) {

		update_event_times(sub);

		if (sub->state == PERF_EVENT_STATE_ACTIVE)

			sub->pmu->read(sub);

	}



unlock:

	raw_spin_unlock(&ctx->lock);

}
@@ -3275,15 +3293,19 @@ u64 perf_event_read_local(struct perf_event *event) 
	return val;

}



static void perf_event_read(struct perf_event *event)

static void perf_event_read(struct perf_event *event, bool group)

{

	/*

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

	 * value in the event structure:

	 */

	if (event->state == PERF_EVENT_STATE_ACTIVE) {

		struct perf_read_data data = {

			.event = event,

			.group = group,

		};

		smp_call_function_single(event->oncpu,

					 __perf_event_read, event, 1);

					 __perf_event_read, &data, 1);

	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {

		struct perf_event_context *ctx = event->ctx;

		unsigned long flags;
@@ -3298,6 +3320,9 @@ static void perf_event_read(struct perf_event *event) 
			update_context_time(ctx);

			update_cgrp_time_from_event(event);

		}

		if (group)

			update_group_times(event);

		else

			update_event_times(event);

		raw_spin_unlock_irqrestore(&ctx->lock, flags);

	}
@@ -3817,7 +3842,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 


	mutex_lock(&event->child_mutex);



	perf_event_read(event);

	perf_event_read(event, false);

	total += perf_event_count(event);



	*enabled += event->total_time_enabled +
@@ -3826,7 +3851,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 
			atomic64_read(&event->child_total_time_running);



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

		perf_event_read(child);

		perf_event_read(child, false);

		total += perf_event_count(child);

		*enabled += child->total_time_enabled;

		*running += child->total_time_running;
@@ -3987,7 +4012,7 @@ static unsigned int perf_poll(struct file *file, poll_table *wait) 


static void _perf_event_reset(struct perf_event *event)

{

	perf_event_read(event);

	perf_event_read(event, false);

	local64_set(&event->count, 0);

	perf_event_update_userpage(event);

}