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Date: Tue, 29 Oct 2024 10:07:36 +0800
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Subject: Re: [RFC PATCH 2/2] sched/eevdf: Introduce a cgroup interface for
 slice
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To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, 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>, Valentin Schneider <vschneid@redhat.com>
References: <20241028063313.8039-1-dtcccc@linux.alibaba.com>
 <20241028063313.8039-3-dtcccc@linux.alibaba.com>
 <Zx_LwYshJV5LERm9@slm.duckdns.org>
From: Tianchen Ding <dtcccc@linux.alibaba.com>
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On 2024/10/29 01:37, Tejun Heo wrote:
> Hello,
> 
> On Mon, Oct 28, 2024 at 02:33:13PM +0800, Tianchen Ding wrote:
>> Introduce "cpu.fair_slice" for cgroup v2 and "cpu.fair_slice_us" for v1
>> according to their name styles. The unit is always microseconds.
>>
>> A cgroup with shorter slice can preempt others more easily. This could be
>> useful in container scenarios.
>>
>> By default, cpu.fair_slice is 0, which means the slice of se is
>> calculated by min_slice from its cfs_rq. If cpu.fair_slice is set, it
>> will overwrite se->slice with the customized value.
> 
> Provided that this tunable is necessary, wouldn't it be more useful to
> figure out what per-task interface would look like first? Maybe there are
> cases where per-cgroup slice config makes sense but that sounds
> significantly less useful than being able to configure it per-task.
> 
> Thanks.
> 

For eevdf, per-task interface has been introduced in commit 857b158dc5e8 
("sched/eevdf: Use sched_attr::sched_runtime to set request/slice suggestion")

So This patch is trying to introduce a cgroup level interface.

Thanks.