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From:   Josh Don <joshdon@google.com>
Date:   Wed, 8 Sep 2021 11:36:20 -0700
Message-ID: <CABk29NtMdwYACJ4k5R=tz66_GFeFf8uTOK000baz6PCbdJAcrg@mail.gmail.com>
Subject: Re: [PATCH v3 1/4] sched: cgroup SCHED_IDLE support
To:     alexs@kernel.org
Cc:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Paul Turner <pjt@google.com>,
        Oleg Rombakh <olegrom@google.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Steve Sistare <steven.sistare@oracle.com>,
        Tejun Heo <tj@kernel.org>, Rik van Riel <riel@surriel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Mon, Sep 6, 2021 at 5:47 AM <alexs@kernel.org> wrote:
>
> ...
>
> > For now, we maintain the existing SCHED_IDLE semantics. Future patches
> > may make improvements that extend how we treat SCHED_IDLE entities.
> >
> > The per-task_group idle field is an integer that currently only holds
> > either a 0 or a 1. This is explicitly typed as an integer to allow for
> > further extensions to this API. For example, a negative value may
> > indicate a highly latency-sensitive cgroup that should be preferred for
> > preemption/placement/etc.
>
> Hi Josh,
>
> Sounds there is a ready solutions for colocation problem, isn't there?
> I'd like to evaluate its effects if it could be sent out.
>
> Thanks
> Alex
> >

Hi Alex,

I don't have a patch written just yet. The basic idea is to utilize
the (negative) idle values to make relative decisions about task
preemption and wakeup vruntime placement.

Could you describe your use case?

Best,
Josh