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From: Peter Zijlstra <peterz@infradead.org>
To: Mike Turquette <mturquette@linaro.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
	preeti@linux.vnet.ibm.com, Morten.Rasmussen@arm.com,
	kamalesh@linux.vnet.ibm.com, riel@redhat.com, efault@gmx.de,
	nicolas.pitre@linaro.org, linaro-kernel@lists.linaro.org,
	daniel.lezcano@linaro.org, dietmar.eggemann@arm.com,
	pjt@google.com, bsegall@google.com, vincent.guittot@linaro.org,
	patches@linaro.org, tuukka.tikkanen@linaro.org,
	amit.kucheria@linaro.org
Subject: Re: [PATCH RFC 7/7] sched: energy_model: simple cpu frequency scaling policy
Date: Tue, 28 Oct 2014 15:27:49 +0100	[thread overview]
Message-ID: <20141028142749.GO3219@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1413958051-7103-8-git-send-email-mturquette@linaro.org>

On Tue, Oct 21, 2014 at 11:07:31PM -0700, Mike Turquette wrote:
> Unlike legacy CPUfreq governors, this policy does not implement its own
> logic loop (such as a workqueue triggered by a timer), but instead uses
> an event-driven design. Frequency is evaluated by entering
> {en,de}queue_task_fair and then a kthread is woken from
> run_rebalance_domains which scales cpu frequency based on the latest
> evaluation.

Also note that we probably want to extend the governor to include the
other sched classes, deadline for example is a good candidate to include
as it already explicitly provides utilization requirements from which
you can compute a hard minimum frequency, below which the task set is
unschedulable.

fifo/rr are far harder to do, since for them we don't have anything
useful, the best we can do I suppose is some statistical over
provisioning but no guarantees.



      parent reply	other threads:[~2014-10-28 14:28 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-22  6:07 [PATCH RFC 0/7] scheduler-driven cpu frequency scaling Mike Turquette
2014-10-22  6:07 ` [PATCH RFC 1/7] sched: Make energy awareness a sched feature Mike Turquette
2014-10-22  6:07 ` [PATCH RFC 2/7] sched: cfs: declare capacity_of in sched.h Mike Turquette
2014-10-22  6:07 ` [PATCH RFC 3/7] sched: fair: add usage_util_of helper Mike Turquette
2014-10-22  6:07 ` [PATCH RFC 4/7] cpufreq: add per-governor private data Mike Turquette
2014-10-22  6:26   ` Viresh Kumar
2014-10-22  6:35     ` Mike Turquette
2014-10-22  6:07 ` [PATCH RFC 5/7] sched: cfs: cpu frequency scaling arch functions Mike Turquette
2014-10-22 20:06   ` Rik van Riel
2014-10-22 23:20     ` Mike Turquette
2014-10-23  1:42       ` Rik van Riel
2014-10-23  2:12         ` Mike Galbraith
2014-10-23  2:42           ` Rik van Riel
2014-10-22  6:07 ` [PATCH RFC 6/7] sched: cfs: cpu frequency scaling based on task placement Mike Turquette
2014-10-23  4:03   ` Preeti U Murthy
2014-10-27 15:55   ` Peter Zijlstra
2014-10-27 17:42   ` Dietmar Eggemann
2014-11-27 10:46   ` Preeti U Murthy
2014-10-22  6:07 ` [PATCH RFC 7/7] sched: energy_model: simple cpu frequency scaling policy Mike Turquette
2014-10-27 19:43   ` Dietmar Eggemann
2014-10-28 14:27   ` Peter Zijlstra [this message]

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