From: Peter Zijlstra <peterz@infradead.org>
To: Leo Yan <leo.yan@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Steve Muckle <steve.muckle@linaro.org>,
linux-kernel@vger.kernel.org, eas-dev@lists.linaro.org
Subject: Re: [PATCH RFC] sched/fair: let cpu's cfs_rq to reflect task migration
Date: Fri, 1 Apr 2016 21:49:48 +0200 [thread overview]
Message-ID: <20160401194948.GN3448@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1459528717-17339-1-git-send-email-leo.yan@linaro.org>
On Sat, Apr 02, 2016 at 12:38:37AM +0800, Leo Yan wrote:
> When task is migrated from CPU_A to CPU_B, scheduler will decrease
> the task's load/util from the task's cfs_rq and also add them into
> migrated cfs_rq. But if kernel enables CONFIG_FAIR_GROUP_SCHED then this
> cfs_rq is not the same one with cpu's cfs_rq. As a result, after task is
> migrated to CPU_B, then CPU_A still have task's stale value for
> load/util; on the other hand CPU_B also cannot reflect new load/util
> which introduced by the task.
>
> So this patch is to operate the task's load/util to cpu's cfs_rq, so
> finally cpu's cfs_rq can really reflect task's migration.
Sorry but that is unintelligible.
What is the problem? Why do we care? How did you fix it? and at what
cost?
next prev parent reply other threads:[~2016-04-01 19:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 16:38 [PATCH RFC] sched/fair: let cpu's cfs_rq to reflect task migration Leo Yan
2016-04-01 19:49 ` Peter Zijlstra [this message]
2016-04-01 22:28 ` Steve Muckle
2016-04-02 7:11 ` Leo Yan
2016-04-04 8:48 ` Morten Rasmussen
2016-04-04 18:30 ` Yuyang Du
2016-04-05 7:51 ` Morten Rasmussen
2016-04-05 0:15 ` Yuyang Du
2016-04-05 17:00 ` Dietmar Eggemann
2016-04-06 8:37 ` Morten Rasmussen
2016-04-06 12:14 ` Vincent Guittot
2016-04-06 18:53 ` Dietmar Eggemann
2016-04-07 13:04 ` Vincent Guittot
2016-04-07 20:30 ` Dietmar Eggemann
2016-04-08 6:05 ` Vincent Guittot
2016-04-05 6:56 ` Leo Yan
2016-04-05 9:13 ` Morten Rasmussen
2016-04-04 9:01 ` Morten Rasmussen
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