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From: Tejun Heo <tj@kernel.org>
To: Josh Don <joshdon@google.com>
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>,
	David Rientjes <rientjes@google.com>,
	Oleg Rombakh <olegrom@google.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Steve Sistare <steven.sistare@oracle.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH] sched: cgroup SCHED_IDLE support
Date: Sat, 26 Jun 2021 05:57:28 -0400	[thread overview]
Message-ID: <YNb6CL6Q9CJnbB2R@mtj.duckdns.org> (raw)
In-Reply-To: <CABk29NtcRUwskBjrvLKkEKQ0hpNPSrdzrGAGZy+bHSfnznOUSg@mail.gmail.com>

Hello,

On Wed, Jun 16, 2021 at 06:01:59PM -0700, Josh Don wrote:
> Consider a tree like
> 
>                   root
>              /             \
>             A              C
>         /      \             |
>       B       idle       t4
>      |           |     \
>      t1         t2   t3
> 
> Here, 'idle' is our cpu.idle cgroup. The following properties would
> not be possible if we moved t2/t3 into SCHED_IDLE without the cgroup
> interface:
> - t1 always preempts t2/t3 on wakeup, but t4 does not
> - t2 and t3 have different, non-minimum weights. Technically we could
> also achieve this by adding another layer of nested cgroups, but that
> starts to make the hierarchy much more complex.
> - I've also discussed with Peter a possible extension (vruntime
> adjustments) to the current SCHED_IDLE semantics. Similarly to the
> first bullet here, we'd need a cgroup idle toggle to achieve certain
> scheduling behaviors with this.

Would you care to share some concrete use cases?

Thank you.

-- 
tejun

  reply	other threads:[~2021-06-26  9:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 23:11 [PATCH] sched: cgroup SCHED_IDLE support Josh Don
2021-06-10 12:53 ` Dietmar Eggemann
2021-06-10 19:14   ` Josh Don
2021-06-11 16:43     ` Dietmar Eggemann
2021-06-11 23:34       ` Josh Don
2021-06-15 10:06         ` Dietmar Eggemann
2021-06-15 23:30           ` Josh Don
2021-06-25  9:24           ` Peter Zijlstra
2021-06-16 15:42 ` Tejun Heo
2021-06-17  1:01   ` Josh Don
2021-06-26  9:57     ` Tejun Heo [this message]
2021-06-29  4:57       ` Josh Don
2021-06-25  8:08   ` Peter Zijlstra
2021-06-26 10:06     ` Tejun Heo
2021-06-26 11:42     ` Rik van Riel
2021-06-25  8:14 ` Peter Zijlstra
2021-06-26  0:18   ` Josh Don
2021-06-25  8:20 ` Peter Zijlstra
2021-06-26  0:35   ` Josh Don

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