From: Yuyang Du <yuyang.du@intel.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Benjamin Segall <bsegall@google.com>,
Paul Turner <pjt@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Matt Fleming <matt@codeblueprint.co.uk>
Subject: Re: [PATCH v6 1/4] sched/fair: Fix attaching task sched avgs twice when switching to fair or changing task group
Date: Wed, 15 Jun 2016 08:18:18 +0800 [thread overview]
Message-ID: <20160615001818.GL8105@intel.com> (raw)
In-Reply-To: <CAKfTPtC6SqsTkH4u6GT_64wwVr9t0mf8J0TchxSQGfbH6oAX9A@mail.gmail.com>
On Wed, Jun 15, 2016 at 09:46:53AM +0200, Vincent Guittot wrote:
> I still have concerned with this change of the behavior that attaches
> the task only when it is enqueued. The load avg of the task will not
> be decayed between the time we move it into its new group until its
> enqueue. With this change, a task's load can stay high whereas it has
> slept for the last couple of seconds.
The task will be updated when it is moved in the detach, so if it stays
high, it is highly expected to be enqueued soon. But if the task is never
enqueued, we don't bother the new gruop cfs_rq.
So this is not perfect, and nothing is perfect, but a simple solution.
next prev parent reply other threads:[~2016-06-15 8:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 22:21 [PATCH v6 0/4] sched/fair: Fix attach and detach sched avgs for task group change and sched class change Yuyang Du
2016-06-14 22:21 ` [PATCH v6 1/4] sched/fair: Fix attaching task sched avgs twice when switching to fair or changing task group Yuyang Du
2016-06-15 7:46 ` Vincent Guittot
2016-06-15 0:18 ` Yuyang Du [this message]
2016-06-15 14:15 ` Vincent Guittot
2016-06-15 15:22 ` Peter Zijlstra
2016-06-16 1:00 ` Yuyang Du
2016-06-16 16:30 ` Vincent Guittot
2016-06-16 17:17 ` Peter Zijlstra
2016-06-16 18:57 ` Vincent Guittot
2016-06-16 18:51 ` Peter Zijlstra
2016-06-16 19:00 ` Vincent Guittot
2016-06-16 20:07 ` Peter Zijlstra
2016-06-16 21:21 ` Vincent Guittot
2016-06-17 2:12 ` Yuyang Du
2016-06-17 12:00 ` Vincent Guittot
2016-06-17 9:48 ` Peter Zijlstra
2016-06-17 11:31 ` Peter Zijlstra
2016-06-14 22:21 ` [PATCH v6 2/4] sched/fair: Move load and util avgs from wake_up_new_task() to sched_fork() Yuyang Du
2016-06-14 22:21 ` [PATCH v6 3/4] sched/fair: Skip detach sched avgs for new task when changing task groups Yuyang Du
2016-06-14 22:21 ` [PATCH v6 4/4] sched/fair: Add inline to detach_entity_load_evg() Yuyang Du
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