From: "tip-bot2 for Vincent Guittot" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/urgent] sched/pelt: Ensure that *_sum is always synced with *_avg
Date: Thu, 03 Jun 2021 11:03:47 -0000 [thread overview]
Message-ID: <162271822738.29796.10300371462032063368.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210601085832.12626-1-vincent.guittot@linaro.org>
The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: fcf6631f3736985ec89bdd76392d3c7bfb60119f
Gitweb: https://git.kernel.org/tip/fcf6631f3736985ec89bdd76392d3c7bfb60119f
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Tue, 01 Jun 2021 10:58:32 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 03 Jun 2021 12:55:55 +02:00
sched/pelt: Ensure that *_sum is always synced with *_avg
Rounding in PELT calculation happening when entities are attached/detached
of a cfs_rq can result into situations where util/runnable_avg is not null
but util/runnable_sum is. This is normally not possible so we need to
ensure that util/runnable_sum stays synced with util/runnable_avg.
detach_entity_load_avg() is the last place where we don't sync
util/runnable_sum with util/runnbale_avg when moving some sched_entities
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210601085832.12626-1-vincent.guittot@linaro.org
---
kernel/sched/fair.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e7c8277..7b98fb3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3765,11 +3765,17 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
*/
static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
+ /*
+ * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+ * See ___update_load_avg() for details.
+ */
+ u32 divider = get_pelt_divider(&cfs_rq->avg);
+
dequeue_load_avg(cfs_rq, se);
sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg);
- sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum);
+ cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * divider;
sub_positive(&cfs_rq->avg.runnable_avg, se->avg.runnable_avg);
- sub_positive(&cfs_rq->avg.runnable_sum, se->avg.runnable_sum);
+ cfs_rq->avg.runnable_sum = cfs_rq->avg.runnable_avg * divider;
add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
prev parent reply other threads:[~2021-06-03 11:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 8:58 [PATCH] sched/pelt: ensure that *_sum is always synced with *_avg Vincent Guittot
2021-06-03 11:03 ` tip-bot2 for Vincent Guittot [this message]
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