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From: Yuyang Du <yuyang.du@intel.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Benjamin Segall <bsegall@google.com>,
	Paul Turner <pjt@google.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>
Subject: Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up
Date: Thu, 2 Jun 2016 03:35:24 +0800	[thread overview]
Message-ID: <20160601193524.GZ18670@intel.com> (raw)
In-Reply-To: <CAKfTPtCH9ycaTfK383b6DqE7JSOwz_e4Xr46S+XF5ZGVE4+_Jg@mail.gmail.com>

On Wed, Jun 01, 2016 at 11:24:45AM +0200, Vincent Guittot wrote:
> >
> > So with the patch, we will have a little bit semantic change, SD_BALANCE_WAKE
> > implies SD_WAKE_AFFINE if allowed, and will favor "fast path" if possible. I don't
> > think we should do anything otherwise.
> 
> Why should we not do anything else ?
> 
> The current default configuration is to only use the wake_affine path.
> With your changes, the default configuration will try to use wake
> affine and will fall back to long load balance sequence if wake affine
> doesn't find a sched_domain
> 
> That's a major changes in the behavior
 
Well, I won't argue that this hasn't changed, but I'd argue that this change
isn't a bad change: (a) it restores the flags to their meanings and makes them
more "elegant", (b) we definitely need further work to improve
select_task_rq_fair(), there has already been a comment marked XXX, right? :)

  reply	other threads:[~2016-06-02  3:32 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-31  1:11 [RFC PATCH 0/2] Remove and replace SD_WAKE_AFFINE with SD_BALANCE_WAKE Yuyang Du
2016-05-31  1:11 ` [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up Yuyang Du
2016-05-31  9:21   ` Peter Zijlstra
2016-05-31  1:31     ` Yuyang Du
2016-05-31 10:41       ` Peter Zijlstra
2016-05-31 18:00         ` Yuyang Du
2016-06-01  5:07       ` Mike Galbraith
2016-06-01  0:01         ` Yuyang Du
2016-06-01  8:32           ` Vincent Guittot
2016-06-01  1:03             ` Yuyang Du
2016-06-01  9:24               ` Vincent Guittot
2016-06-01 19:35                 ` Yuyang Du [this message]
2016-06-02  6:56                   ` Vincent Guittot
2016-06-01 23:19                     ` Yuyang Du
2016-06-01  9:36           ` Mike Galbraith
2016-06-01 20:03             ` Yuyang Du
2016-06-02  5:50               ` Mike Galbraith
2016-06-01 22:41                 ` Yuyang Du
2016-06-02  6:44                   ` Mike Galbraith
2016-05-31  1:11 ` [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE Yuyang Du
2016-05-31  9:23   ` Peter Zijlstra
2016-05-31  1:34     ` Yuyang Du

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