From 20424b480cedaaea10f5c56c6140692c97b9837e Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Wed, 13 Jan 2016 15:49:44 +0000 Subject: [PATCH] sched: Do eas idle balance regardless of the rq avg idle value EAS relies on idle balance to migrate a misfit task towards a cpu with higher capacity. When such a cpu becomes idle, idle balance should happen even if the rq avg idle is smaller than the sched migration cost (default 500us). The rq avg idle is updated during the wakeup of a task in case the rq has a non-null idle_stamp. This value stays unchanged and valid until the next task wakes up on this cpu after an idle period. So rq avg idle could be smaller than sched migration cost preventing the idle balance from happening. In this case we would be at the mercy of wakeup, periodic or nohz-idle load balancing to put another task on this cpu. To break this dependency towards rq avg idle make EAS idle balance independent from this rq avg idle has to be larger than sched migration cost. Signed-off-by: Dietmar Eggemann --- kernel/sched/fair.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 08e2ef16d600..3c2ddfc8cee8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7793,8 +7793,9 @@ static int idle_balance(struct rq *this_rq) */ this_rq->idle_stamp = rq_clock(this_rq); - if (this_rq->avg_idle < sysctl_sched_migration_cost || - !this_rq->rd->overload) { + if (!energy_aware() && + (this_rq->avg_idle < sysctl_sched_migration_cost || + !this_rq->rd->overload)) { rcu_read_lock(); sd = rcu_dereference_check_sched_domain(this_rq->sd); if (sd) -- 2.34.1