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From: Vincent Guittot <vincent.guittot@linaro.org>
To: Yuyang Du <yuyang.du@intel.com>
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 08:56:40 +0200	[thread overview]
Message-ID: <CAKfTPtDveMbwiphH8xBsquYdwind8xXGLqLhpOzgEqPcWdnzhg@mail.gmail.com> (raw)
In-Reply-To: <20160601193524.GZ18670@intel.com>

On 1 June 2016 at 21:35, Yuyang Du <yuyang.du@intel.com> wrote:
> 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

Have you any proof that this change is not a bad thing ? Moreover have
you got proof that it's a good thing ? Changing the meaning and the
behavior of flags, just because you find it elegant, doesn't seem to
be enough for me.

So if you just want to rename the flags please keep current behavior unchange

> 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  6:57 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
2016-06-02  6:56                   ` Vincent Guittot [this message]
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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