sched/fair: Avoid calling sync_entity_load_avg() unnecessarily (c976a862) · Commits · 戴 / test

Call sync_entity_load_avg() directly from find_idlest_cpu() instead of select_task_rq_fair(), as that's where we need to use task's utilization value. And call sync_entity_load_avg() only after making sure sched domain spans over one of the allowed CPUs for the task. Signed-off-by:

Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: http://lkml.kernel.org/r/cd019d1753824c81130eae7b43e2bbcec47cc1ad.1524738578.git.viresh.kumar@linaro.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/sched/fair.c

+7 −9

Original line number	Diff line number	Diff line
		@@ -6199,6 +6199,13 @@ static inline int find_idlest_cpu(struct sched_domain sd, struct task_struct p
		if (!cpumask_intersects(sched_domain_span(sd), &p->cpus_allowed))
		return prev_cpu;

		/*
		* We need task's util for capacity_spare_wake, sync it up to prev_cpu's
		* last_update_time.
		*/
		if (!(sd_flag & SD_BALANCE_FORK))
		sync_entity_load_avg(&p->se);

		while (sd) {
		struct sched_group *group;
		struct sched_domain *tmp;
		@@ -6651,15 +6658,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f

		if (unlikely(sd)) {
		/* Slow path */

		/*
		* We're going to need the task's util for capacity_spare_wake
		* in find_idlest_group. Sync it up to prev_cpu's
		* last_update_time.
		*/
		if (!(sd_flag & SD_BALANCE_FORK))
		sync_entity_load_avg(&p->se);

		new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
		} else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */
		/* Fast path */

Admin message