From: Chengming Zhou <zhouchengming@bytedance.com>
To: mingo@redhat.com, peterz@infradead.org,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, vschneid@redhat.com
Cc: linux-kernel@vger.kernel.org,
Chengming Zhou <zhouchengming@bytedance.com>
Subject: [PATCH v2 09/10] sched/fair: stop load tracking when task switched_from_fair()
Date: Wed, 13 Jul 2022 12:04:29 +0800 [thread overview]
Message-ID: <20220713040430.25778-10-zhouchengming@bytedance.com> (raw)
In-Reply-To: <20220713040430.25778-1-zhouchengming@bytedance.com>
The same reason as the previous commit, if we don't reset the
sched_avg last_update_time to 0, after a while in switched_to_fair():
switched_to_fair
attach_task_cfs_rq
attach_entity_cfs_rq
update_load_avg
__update_load_avg_se(now, cfs_rq, se)
The delta (now - sa->last_update_time) will wrongly contribute/decay
sched_avg depends on the task running/runnable status at that time.
This patch reset it's sched_avg last_update_time to 0, stop load
tracking for !fair task, later in switched_to_fair() ->
update_load_avg(), we can use its saved sched_avg.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
kernel/sched/fair.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 50f65a2ede32..576028f5a09e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -11552,6 +11552,11 @@ static void attach_task_cfs_rq(struct task_struct *p)
static void switched_from_fair(struct rq *rq, struct task_struct *p)
{
detach_task_cfs_rq(p);
+
+#ifdef CONFIG_SMP
+ /* Stop load tracking for !fair task */
+ p->se.avg.last_update_time = 0;
+#endif
}
static void switched_to_fair(struct rq *rq, struct task_struct *p)
--
2.36.1
next prev parent reply other threads:[~2022-07-13 4:05 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 4:04 [PATCH v2 00/10] sched: task load tracking optimization and cleanup Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 01/10] sched/fair: combine detach into dequeue when migrating task Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 02/10] sched/fair: update comments in enqueue/dequeue_entity() Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 03/10] sched/fair: maintain task se depth in set_task_rq() Chengming Zhou
2022-07-14 12:30 ` Dietmar Eggemann
2022-07-14 13:03 ` [External] " Chengming Zhou
2022-07-18 7:16 ` Vincent Guittot
2022-07-13 4:04 ` [PATCH v2 04/10] sched/fair: remove redundant cpu_cgrp_subsys->fork() Chengming Zhou
2022-07-14 12:31 ` Dietmar Eggemann
2022-07-14 13:06 ` [External] " Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 05/10] sched/fair: reset sched_avg last_update_time before set_task_rq() Chengming Zhou
2022-07-14 12:31 ` Dietmar Eggemann
2022-07-19 8:49 ` Vincent Guittot
2022-07-13 4:04 ` [PATCH v2 06/10] sched/fair: delete superfluous SKIP_AGE_LOAD Chengming Zhou
2022-07-14 12:33 ` Dietmar Eggemann
2022-07-14 13:24 ` [External] " Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 07/10] sched/fair: use update_load_avg() to attach/detach entity load_avg Chengming Zhou
2022-07-15 11:18 ` Dietmar Eggemann
2022-07-15 16:21 ` [External] " Chengming Zhou
2022-07-19 10:29 ` Vincent Guittot
2022-07-20 13:40 ` Chengming Zhou
2022-07-20 15:34 ` Vincent Guittot
2022-07-21 13:56 ` Chengming Zhou
2022-07-21 14:13 ` Vincent Guittot
2022-07-19 15:02 ` Dietmar Eggemann
2022-07-20 13:43 ` Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 08/10] sched/fair: fix load tracking for new forked !fair task Chengming Zhou
2022-07-19 12:35 ` Vincent Guittot
2022-07-20 13:48 ` [External] " Chengming Zhou
2022-07-13 4:04 ` Chengming Zhou [this message]
2022-07-14 12:33 ` [PATCH v2 09/10] sched/fair: stop load tracking when task switched_from_fair() Dietmar Eggemann
2022-07-14 13:43 ` [External] " Chengming Zhou
2022-07-15 11:15 ` Dietmar Eggemann
2022-07-15 16:35 ` Chengming Zhou
2022-07-19 13:20 ` Vincent Guittot
2022-07-27 10:55 ` Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 10/10] sched/fair: delete superfluous set_task_rq_fair() Chengming Zhou
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