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 08/10] sched/fair: fix load tracking for new forked !fair task
Date: Wed, 13 Jul 2022 12:04:28 +0800 [thread overview]
Message-ID: <20220713040430.25778-9-zhouchengming@bytedance.com> (raw)
In-Reply-To: <20220713040430.25778-1-zhouchengming@bytedance.com>
New forked !fair task will set its sched_avg last_update_time to
the pelt_clock of cfs_rq, 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 contribute/decay sched_avg
depends on the task running/runnable status at that time.
This patch don't set sched_avg last_update_time of new forked !fair
task, leave it to 0. So later in update_load_avg(), we don't need to
contribute/decay the wrong delta (now - sa->last_update_time).
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
kernel/sched/fair.c | 18 ++----------------
1 file changed, 2 insertions(+), 16 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 51fc20c161a3..50f65a2ede32 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -849,22 +849,8 @@ void post_init_entity_util_avg(struct task_struct *p)
sa->runnable_avg = sa->util_avg;
- if (p->sched_class != &fair_sched_class) {
- /*
- * For !fair tasks do:
- *
- update_cfs_rq_load_avg(now, cfs_rq);
- attach_entity_load_avg(cfs_rq, se);
- switched_from_fair(rq, p);
- *
- * such that the next switched_to_fair() has the
- * expected state.
- */
- se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq);
- return;
- }
-
- attach_entity_cfs_rq(se);
+ if (p->sched_class == &fair_sched_class)
+ attach_entity_cfs_rq(se);
}
#else /* !CONFIG_SMP */
--
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 ` Chengming Zhou [this message]
2022-07-19 12:35 ` [PATCH v2 08/10] sched/fair: fix load tracking for new forked !fair task Vincent Guittot
2022-07-20 13:48 ` [External] " Chengming Zhou
2022-07-13 4:04 ` [PATCH v2 09/10] sched/fair: stop load tracking when task switched_from_fair() Chengming Zhou
2022-07-14 12:33 ` 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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