From: Matt Fleming <matt@codeblueprint.co.uk>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Yuyang Du <yuyang.du@intel.com>
Subject: Re: [PATCH] sched/fair: Do not decay new task load on first enqueue
Date: Tue, 27 Sep 2016 20:24:04 +0100 [thread overview]
Message-ID: <20160927192404.GC16071@codeblueprint.co.uk> (raw)
In-Reply-To: <1774604b-1028-a4b1-a254-b2fb32cd91f1@arm.com>
On Tue, 27 Sep, at 02:48:31PM, Dietmar Eggemann wrote:
>
> I think Matt is talking about the fact that the cfs->runnable_load_avg
> value is 0 once the hackbench task is initially dequeued.
Yes.
> Without this patch the value of se->avg.load_avg (e.g. both times 1002)
> is exactly the same when we add it to cfs_rq->runnable_load_avg in
> enqueue_entity_load_avg() and when we subtract it in
> dequeue_entity_load_avg(). That's because the initial runtime is short
> (~250us on my hikey board).
>
> With this patch we add 1024 and subtract ~1002 which lets
> cfs_rq->runnable_load_avg still have a small positive value. This
> favours that for the next hackbench task another cpu will be chosen in
> (load-based) fork-balance.
Bingo, that's exactly it. Sorry if i was unclear.
next prev parent reply other threads:[~2016-09-27 19:24 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-23 11:58 [PATCH] sched/fair: Do not decay new task load on first enqueue Matt Fleming
2016-09-23 14:30 ` Vincent Guittot
2016-09-27 13:48 ` Dietmar Eggemann
2016-09-27 19:24 ` Matt Fleming [this message]
2016-09-27 19:21 ` Matt Fleming
2016-09-28 10:14 ` Peter Zijlstra
2016-09-28 11:06 ` Dietmar Eggemann
2016-09-28 11:19 ` Peter Zijlstra
2016-09-28 11:31 ` Dietmar Eggemann
2016-09-28 11:46 ` Vincent Guittot
2016-09-28 12:00 ` Vincent Guittot
2016-10-04 21:25 ` Matt Fleming
2016-10-04 20:16 ` Matt Fleming
2016-09-28 12:27 ` Vincent Guittot
2016-09-28 13:13 ` Vincent Guittot
2016-09-29 16:15 ` Dietmar Eggemann
2016-10-03 13:05 ` Vincent Guittot
2016-09-28 17:59 ` Dietmar Eggemann
2016-09-28 19:37 ` Matt Fleming
2016-09-30 20:30 ` Matt Fleming
2016-10-09 3:39 ` Wanpeng Li
2016-10-10 10:01 ` Matt Fleming
2016-10-10 10:09 ` Wanpeng Li
2016-10-11 10:27 ` Matt Fleming
2016-10-10 12:29 ` Vincent Guittot
2016-10-10 13:54 ` Dietmar Eggemann
2016-10-10 18:29 ` Vincent Guittot
2016-10-11 9:44 ` Dietmar Eggemann
2016-10-11 10:39 ` Matt Fleming
2016-10-18 10:11 ` Matt Fleming
2016-10-10 17:34 ` Vincent Guittot
2016-10-11 10:24 ` Matt Fleming
2016-10-11 13:14 ` Vincent Guittot
2016-10-11 18:57 ` Matt Fleming
2016-10-12 7:41 ` Vincent Guittot
2016-10-18 11:09 ` Peter Zijlstra
2016-10-18 15:19 ` Vincent Guittot
2016-10-18 10:29 ` Matt Fleming
2016-10-18 11:10 ` Peter Zijlstra
2016-10-18 11:29 ` Matt Fleming
2016-10-18 12:15 ` Peter Zijlstra
2016-10-19 6:38 ` Vincent Guittot
2016-10-19 9:53 ` Peter Zijlstra
2016-11-09 16:53 ` Vincent Guittot
2016-10-04 20:11 ` Matt Fleming
2016-10-09 5:57 ` [sched/fair] f54c5d4e28: hackbench.throughput 10.6% improvement kernel test robot
2016-10-09 5:57 ` [lkp] " kernel test robot
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