Groups > linux.kernel > #1411948

Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task

From	Vincent Guittot <vincent.guittot@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task
Date	2016-06-02 09:50 +0200
Message-ID	<rFvy9-32D-1@gated-at.bofh.it> (permalink)
References	(1 earlier) <rFcFc-7Qb-33@gated-at.bofh.it> <rFdrA-8lQ-11@gated-at.bofh.it> <rFrkR-xA-3@gated-at.bofh.it> <rFvou-2Z6-29@gated-at.bofh.it> <rFvy9-32D-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 2 June 2016 at 01:41, Yuyang Du <yuyang.du@intel.com> wrote:
> On Thu, Jun 02, 2016 at 09:29:53AM +0200, Vincent Guittot wrote:
>> > My response to your above two comments:
>> >
>> > As I said, there can be four possibilities going through the above sequences:
>> >
>> > (1) on_rq, (2) !on_rq, (a) was fair class (representing last_update_time != 0),
>> > (b) never was fair class (representing last_update_time == 0, but may not be
>> > limited to this)
>> >
>> > Crossing them, we have (1)(a), (1)(b), (2)(a), and (2)(b).
>> >
>> > Some will attach twice, which are (1)(b) and (2)(b), the other will attach
>> > once, which are (1)(a) and (2)(a). The difficult part is they can be attached
>> > at different places.
>>
>> ok for (1)(b) but not for (2)(b) and it's far from "attached mostly
>> twice every time"
>
> You are right. That claim is reckless, I will change it to:
> "sometimes attached twice".

Or you can just describe the used case (1)(b) which is the only one AFAICT

Thread

[PATCH v3 0/5] sched/fair: Fix attach and detach sched avgs for task group change or sched class change Yuyang Du <yuyang.du@intel.com> - 2016-06-01 13:40 +0200
  [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Yuyang Du <yuyang.du@intel.com> - 2016-06-01 13:40 +0200
    Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-01 14:30 +0200
      Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Yuyang Du <yuyang.du@intel.com> - 2016-06-02 05:20 +0200
        Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-02 09:40 +0200
          Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-02 09:50 +0200
            Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Yuyang Du <yuyang.du@intel.com> - 2016-06-02 09:50 +0200
          Re: [PATCH v3 2/5] sched/fair: Skip detach and attach new group task Yuyang Du <yuyang.du@intel.com> - 2016-06-02 09:50 +0200
  [PATCH v3 4/5] sched/fair: Move load and util avgs from wake_up_new_task() to sched_fork() Yuyang Du <yuyang.du@intel.com> - 2016-06-01 13:40 +0200
    Re: [PATCH v3 4/5] sched/fair: Move load and util avgs from  wake_up_new_task() to sched_fork() Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-01 14:30 +0200
      Re: [PATCH v3 4/5] sched/fair: Move load and util avgs from  wake_up_new_task() to sched_fork() Yuyang Du <yuyang.du@intel.com> - 2016-06-02 05:00 +0200

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