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From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Thu, 22 Sep 2022 08:40:36 +0200
Message-ID: <CAKfTPtD1P0oTf6drOW9XwVnQ8MsCihs0rV6j+L2HV93JP-U9Lg@mail.gmail.com>
Subject: Re: [PATCH v4 6/8] sched/fair: Add sched group latency support
To:     Tejun Heo <tj@kernel.org>
Cc:     Qais Yousef <qais.yousef@arm.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>, mingo@redhat.com,
        peterz@infradead.org, juri.lelli@redhat.com, rostedt@goodmis.org,
        bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
        vschneid@redhat.com, linux-kernel@vger.kernel.org,
        parth@linux.ibm.com, chris.hyser@oracle.com,
        valentin.schneider@arm.com, patrick.bellasi@matbug.net,
        David.Laight@aculab.com, pjt@google.com, pavel@ucw.cz,
        qperret@google.com, tim.c.chen@linux.intel.com, joshdon@google.com
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On Wed, 21 Sept 2022 at 19:12, Tejun Heo <tj@kernel.org> wrote:
>
> On Wed, Sep 21, 2022 at 07:02:57PM +0200, Vincent Guittot wrote:
> > > One option could be just using the same mapping as cpu.weight so that 100
> > > maps to neutral, 10000 maps close to -20, 1 maps close to 19. It isn't great
> > > that the value can't be interpreted in any intuitive way (e.g. a time
> > > duration based interface would be a lot easier to grok even if it still is
> > > best effort) but if that's what the per-task interface is gonna be, it'd be
> > > best to keep cgroup interface in line.
> >
> > I would prefer a signed range like the [-1000:1000] as the behavior is
> > different for sensitive and non sensitive task unlike the cpu.weight
> > which is reflect that a bigger value get more
>
> How about just sticking with .nice?

Looks good to me. I will just implement the cpu.latency.nice

>
> --
> tejun