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From: Juri Lelli <juri.lelli@redhat.com>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Paul Turner <pjt@google.com>,
	Quentin Perret <quentin.perret@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Todd Kjos <tkjos@google.com>, Joel Fernandes <joelaf@google.com>,
	Steve Muckle <smuckle@google.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	linux-api@vger.kernel.org
Subject: Re: [PATCH v4 01/16] sched/core: uclamp: extend sched_setattr to support utilization clamping
Date: Wed, 5 Sep 2018 13:01:08 +0200	[thread overview]
Message-ID: <20180905110108.GC20267@localhost.localdomain> (raw)
In-Reply-To: <20180828135324.21976-2-patrick.bellasi@arm.com>

Hi,

On 28/08/18 14:53, Patrick Bellasi wrote:

[...]

> Let's introduce a new API to set utilization clamping values for a
> specified task by extending sched_setattr, a syscall which already
> allows to define task specific properties for different scheduling
> classes.
> Specifically, a new pair of attributes allows to specify a minimum and
> maximum utilization which the scheduler should consider for a task.

AFAIK sched_setattr currently mandates that a policy is always specified
[1]. I was wondering if relaxing such requirement might be handy. Being
util clamp a cross-class feature it might be cumbersome to always have
to get current policy/params and use those with new umin/umax just to
change the latter.

sched_setparam already uses the in-kernel SETPARAM_POLICY thing, maybe
we could extend that to sched_setattr? Not sure exposing this to
userspace is a good idea though. :-/

Best,

- Juri

1 - https://elixir.bootlin.com/linux/v4.19-rc2/source/kernel/sched/core.c#L4564

      reply	other threads:[~2018-09-05 11:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-28 13:53 [PATCH v4 00/16] Add utilization clamping support Patrick Bellasi
2018-08-28 13:53 ` [PATCH v4 01/16] sched/core: uclamp: extend sched_setattr to support utilization clamping Patrick Bellasi
2018-09-05 11:01   ` Juri Lelli [this message]

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