Commit f269ae04 authored by Paul Turner's avatar Paul Turner Committed by Ingo Molnar
Browse files

sched: Update_cfs_shares at period edge 



Now that our measurement intervals are small (~1ms) we can amortize the posting
of update_shares() to be about each period overflow.  This is a large cost
saving for frequently switching tasks.

Signed-off-by: default avatarPaul Turner <pjt@google.com>
Reviewed-by: default avatarBen Segall <bsegall@google.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.200772172@google.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 48a16753

kernel/sched/fair.c

+10 −8
Original line number Diff line number Diff line
@@ -1187,6 +1187,7 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update) 
	}



	__update_cfs_rq_tg_load_contrib(cfs_rq, force_update);

	update_cfs_shares(cfs_rq);

}



static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
@@ -1396,9 +1397,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
	 * Update run-time statistics of the 'current'.

	 */

	update_curr(cfs_rq);

	enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP);

	account_entity_enqueue(cfs_rq, se);

	update_cfs_shares(cfs_rq);

	enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP);



	if (flags & ENQUEUE_WAKEUP) {

		place_entity(cfs_rq, se, 0);
@@ -1471,7 +1471,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
	 * Update run-time statistics of the 'current'.

	 */

	update_curr(cfs_rq);

	dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP);



	update_stats_dequeue(cfs_rq, se);

	if (flags & DEQUEUE_SLEEP) {
@@ -1491,8 +1490,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 


	if (se != cfs_rq->curr)

		__dequeue_entity(cfs_rq, se);

	se->on_rq = 0;

	account_entity_dequeue(cfs_rq, se);

	dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP);



	/*

	 * Normalize the entity after updating the min_vruntime because the
@@ -1506,7 +1505,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
	return_cfs_rq_runtime(cfs_rq);



	update_min_vruntime(cfs_rq);

	update_cfs_shares(cfs_rq);

	se->on_rq = 0;

}



/*
@@ -2518,8 +2517,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
		if (cfs_rq_throttled(cfs_rq))

			break;



		update_cfs_shares(cfs_rq);

		update_entity_load_avg(se, 1);

		update_cfs_rq_blocked_load(cfs_rq, 0);

	}



	if (!se) {
@@ -2579,8 +2578,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
		if (cfs_rq_throttled(cfs_rq))

			break;



		update_cfs_shares(cfs_rq);

		update_entity_load_avg(se, 1);

		update_cfs_rq_blocked_load(cfs_rq, 0);

	}



	if (!se) {
@@ -5639,8 +5638,11 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) 
		se = tg->se[i];

		/* Propagate contribution to hierarchy */

		raw_spin_lock_irqsave(&rq->lock, flags);

		for_each_sched_entity(se)

		for_each_sched_entity(se) {

			update_cfs_shares(group_cfs_rq(se));

			/* update contribution to parent */

			update_entity_load_avg(se, 1);

		}

		raw_spin_unlock_irqrestore(&rq->lock, flags);

	}

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