Commit 41e0d37f authored by Steve Muckle's avatar Steve Muckle Committed by Ingo Molnar
Browse files

sched/fair: Do not call cpufreq hook unless util changed 



There's no reason to call the cpufreq hook if the root cfs_rq
utilization has not been modified.

Signed-off-by: default avatarSteve Muckle <smuckle@linaro.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <Juri.Lelli@arm.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/1458606068-7476-2-git-send-email-smuckle@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 21e96f88

kernel/sched/fair.c

+6 −4
Original line number Diff line number Diff line
@@ -2879,20 +2879,21 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) 
{

	struct sched_avg *sa = &cfs_rq->avg;

	struct rq *rq = rq_of(cfs_rq);

	int decayed, removed = 0;

	int decayed, removed_load = 0, removed_util = 0;

	int cpu = cpu_of(rq);



	if (atomic_long_read(&cfs_rq->removed_load_avg)) {

		s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);

		sa->load_avg = max_t(long, sa->load_avg - r, 0);

		sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);

		removed = 1;

		removed_load = 1;

	}



	if (atomic_long_read(&cfs_rq->removed_util_avg)) {

		long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0);

		sa->util_avg = max_t(long, sa->util_avg - r, 0);

		sa->util_sum = max_t(s32, sa->util_sum - r * LOAD_AVG_MAX, 0);

		removed_util = 1;

	}



	decayed = __update_load_avg(now, cpu, sa,
@@ -2903,7 +2904,8 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) 
	cfs_rq->load_last_update_time_copy = sa->last_update_time;

#endif



	if (cpu == smp_processor_id() && &rq->cfs == cfs_rq) {

	if (cpu == smp_processor_id() && &rq->cfs == cfs_rq &&

	    (decayed || removed_util)) {

		unsigned long max = rq->cpu_capacity_orig;



		/*
@@ -2926,7 +2928,7 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) 
				    min(sa->util_avg, max), max);

	}



	return decayed || removed;

	return decayed || removed_load;

}



/* Update task and its cfs_rq load average */

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