The following commit has been merged into the sched/core branch of tip: Commit-ID: 83c5e9d573e1f0757f324d01adb6ee77b49c3f0e Gitweb: https://git.kernel.org/tip/83c5e9d573e1f0757f324d01adb6ee77b49c3f0e Author: Dietmar Eggemann <dietmar.eggemann@xxxxxxx> AuthorDate: Tue, 01 Jun 2021 10:36:16 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Thu, 17 Jun 2021 14:11:42 +02:00 sched/fair: Return early from update_tg_cfs_load() if delta == 0 In case the _avg delta is 0 there is no need to update se's _avg (level n) nor cfs_rq's _avg (level n-1). These values stay the same. Since cfs_rq's _avg isn't changed, i.e. no load is propagated down, cfs_rq's _sum should stay the same as well. So bail out after se's _sum has been updated. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210601083616.804229-1-dietmar.eggemann@xxxxxxx --- kernel/sched/fair.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 198514d..06c8ba7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3502,9 +3502,12 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq load_sum = (s64)se_weight(se) * runnable_sum; load_avg = div_s64(load_sum, divider); + se->avg.load_sum = runnable_sum; + delta = load_avg - se->avg.load_avg; + if (!delta) + return; - se->avg.load_sum = runnable_sum; se->avg.load_avg = load_avg; add_positive(&cfs_rq->avg.load_avg, delta);
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