Groups > linux.kernel > #1411918

Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up

From	Vincent Guittot <vincent.guittot@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up
Date	2016-06-02 09:00 +0200
Message-ID	<rFuLL-2xr-13@gated-at.bofh.it> (permalink)
References	(5 earlier) <rF9ej-5BV-39@gated-at.bofh.it> <rF9R1-641-61@gated-at.bofh.it> <rFak1-6tA-15@gated-at.bofh.it> <rFaDo-6Ci-27@gated-at.bofh.it> <rFrEd-Dz-3@gated-at.bofh.it>
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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? :)

Thread

[RFC PATCH 0/2] Remove and replace SD_WAKE_AFFINE with SD_BALANCE_WAKE Yuyang Du <yuyang.du@intel.com> - 2016-05-31 11:10 +0200
  [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE Yuyang Du <yuyang.du@intel.com> - 2016-05-31 11:10 +0200
    Re: [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it  with SD_BALANCE_WAKE Peter Zijlstra <peterz@infradead.org> - 2016-05-31 11:30 +0200
      Re: [RFC PATCH 2/2] sched: Remove SD_WAKE_AFFINE flag and replace it  with SD_BALANCE_WAKE Yuyang Du <yuyang.du@intel.com> - 2016-05-31 11:40 +0200
  [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-05-31 11:10 +0200
    Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-05-31 11:30 +0200
      Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Peter Zijlstra <peterz@infradead.org> - 2016-05-31 12:50 +0200
        Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-01 04:00 +0200
      Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-06-01 07:10 +0200
        Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-01 10:00 +0200
          Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-01 10:40 +0200
            Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-01 11:10 +0200
              Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-01 11:30 +0200
                Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-02 05:40 +0200
                Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-02 09:00 +0200
                Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-02 09:20 +0200
          Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-06-01 11:40 +0200
            Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-02 06:10 +0200
              Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-06-02 08:00 +0200
                Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Yuyang Du <yuyang.du@intel.com> - 2016-06-02 08:40 +0200
                Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-06-02 08:50 +0200
    Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched  domain build-up Peter Zijlstra <peterz@infradead.org> - 2016-05-31 11:30 +0200

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