linux-kernel - Re: [PATCH 1/3] sched/fair: Peter's shares

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Message-ID: <CAKfTPtC-Z=zQB6W=TxaqBDVv0B6aww3xrRm50bgiNsWnkkoZ0w@mail.gmail.com>
Date:   Wed, 10 May 2017 18:07:14 +0200
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     Tejun Heo <tj@...nel.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Galbraith <efault@....de>, Paul Turner <pjt@...gle.com>,
        Chris Mason <clm@...com>, kernel-team@...com
Subject: Re: [PATCH 1/3] sched/fair: Peter's shares_type patch

On 10 May 2017 at 17:09, Tejun Heo <tj@...nel.org> wrote:
> Hello, Vincent.
>
> On Fri, May 05, 2017 at 11:30:31AM -0400, Tejun Heo wrote:
>> > For shares_runnable, it should be
>> >
>> > group_entity->runnable_load_avg = cfs_rq->runnable_load_avg *
>> > group_entity->avg.load_avg / cfs_rq->avg.load_avg
>>
>> Yeah, that could be one way to calculate the value while avoiding the
>> artifacts.  Hmmm... IIUC, replacing the local contribution with the
>> current one is to ensure that we at least calculate with the current
>> term on the local queue.  This makes sense for weight and shares but
>> as you pointed out it doesn't make sense to replace local base with
>> runnable when the base is expected to be sum of load_avgs.  How about
>> something like the following?
>
> Vincent, have you given this patch a try?

No I haven't.
My understand of Peter's feedback is that calc_cfs_shares should not
be the place where to implement calculation of
group_entity->runnable_load_avg and group_entity->avg.load_avg when
propagating

>
> Also, I got the hikey board but of course it can't be powered by usb,
> so am waiting on the power supply now.  Any chance you can share the
> system image you're using so that I can exactly replicate your
> environment?

Yes of course.
I will send you details in a dedicated email.

Regards,
Vincent

>
> Thanks.
>
> --
> tejun