Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 25 Jun 2021 11:24:22 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc:     Josh Don <joshdon@google.com>, Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        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>,
        David Rientjes <rientjes@google.com>,
        Oleg Rombakh <olegrom@google.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Steve Sistare <steven.sistare@oracle.com>,
        Tejun Heo <tj@kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: cgroup SCHED_IDLE support
Message-ID: <YNWgxrX4xfa8l0oF@hirez.programming.kicks-ass.net>
References: <20210608231132.32012-1-joshdon@google.com>
 <e3fc3338-c469-0c0c-ada2-a0bbc9f969fe@arm.com>
 <CABk29Nu=mxz3tugjhDV9xCF7DRsMi9U747H+BqubviEva36RUw@mail.gmail.com>
 <7222c20a-5cbb-d443-a2fd-19067652a38e@arm.com>
 <CABk29NtVRG8cotfbK=R0kKXuKCnkEG514H=6ncri=CM8Qr9uiQ@mail.gmail.com>
 <f48b5233-ce60-7e1a-02e6-1bfbcc852271@arm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <f48b5233-ce60-7e1a-02e6-1bfbcc852271@arm.com>
Precedence: bulk

On Tue, Jun 15, 2021 at 12:06:57PM +0200, Dietmar Eggemann wrote:

> I agree. `cpu.idle = 1` is like setting the task policy to SCHED_IDLE.
> And there is even the `cpu.weight.nice` to support the `task - tg`
> analogy on nice values.
> 
> I'm just wondering if integrating this into `cpu.weight` and friends
> would be better to make the code behind this easier to grasp.

Magic weight values are dodgy imo. Easiest to have an explicit idle knob
which then disables the weight knobs.