From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Alex Shi <alex.shi@intel.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
vincent.guittot@linaro.org, svaidy@linux.vnet.ibm.com,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Paul Turner <pjt@google.com>
Subject: Re: [discussion]sched: a rough proposal to enable power saving in scheduler
Date: Mon, 20 Aug 2012 19:16:51 +0100 [thread overview]
Message-ID: <20120820181651.GA737@srcf.ucam.org> (raw)
In-Reply-To: <20120820080606.GA6931@gmail.com>
On Mon, Aug 20, 2012 at 10:06:06AM +0200, Ingo Molnar wrote:
> If the answer is 'yes' then there's clear cases where the kernel
> (should) automatically know the events where we switch from
> balancing for performance to balancing for power:
No. We can't identify all of these cases and we can't identify corner
cases. Putting this kind of policy in the kernel is an awful idea. It
should never be altering policy itself, because it'll get it wrong and
people will file bugs complaining that it got it wrong and the biggest
case where you *need* to be able to handle switching between performance
and power optimisations (your rack management unit just told you that
you're going to have to drop power consumption by 20W) is one where the
kernel doesn't have all the information it needs to do this. So why
bother at all?
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-08-20 18:17 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-13 12:21 [discussion]sched: a rough proposal to enable power saving in scheduler Alex Shi
2012-08-14 7:35 ` Alex Shi
2012-08-15 8:23 ` Peter Zijlstra
2012-08-15 11:05 ` Peter Zijlstra
2012-08-15 13:15 ` Borislav Petkov
2012-08-15 14:43 ` Peter Zijlstra
2012-08-16 3:22 ` Alex Shi
2012-08-16 3:09 ` Alex Shi
2012-08-15 13:45 ` Arjan van de Ven
2012-08-15 14:39 ` Peter Zijlstra
2012-08-15 14:43 ` Arjan van de Ven
2012-08-15 15:04 ` Peter Zijlstra
2012-08-15 17:59 ` Arjan van de Ven
2012-08-20 8:06 ` Ingo Molnar
2012-08-20 8:26 ` Peter Zijlstra
2012-08-20 13:26 ` Arjan van de Ven
2012-08-20 18:16 ` Matthew Garrett [this message]
2012-08-21 9:42 ` Ingo Molnar
2012-08-21 11:39 ` Matthew Garrett
2012-08-21 15:19 ` Ingo Molnar
2012-08-21 15:21 ` Arjan van de Ven
2012-08-21 15:28 ` Matthew Garrett
2012-08-21 15:59 ` Ingo Molnar
2012-08-21 16:13 ` Matthew Garrett
2012-08-21 18:23 ` Ingo Molnar
2012-08-21 18:34 ` Matthew Garrett
2012-08-22 9:10 ` Ingo Molnar
2012-08-22 11:35 ` Matthew Garrett
2012-08-23 8:19 ` Alex Shi
2012-08-21 18:52 ` Alan Cox
2012-08-22 9:03 ` Ingo Molnar
2012-08-22 11:00 ` Alan Cox
2012-08-22 11:33 ` Ingo Molnar
2012-08-22 12:58 ` Alan Cox
2012-08-21 16:02 ` Alan Cox
2012-08-22 5:41 ` Mike Galbraith
2012-08-22 13:02 ` Arjan van de Ven
2012-08-22 13:09 ` Mike Galbraith
2012-08-22 13:21 ` Matthew Garrett
2012-08-22 13:23 ` Arjan van de Ven
2012-08-16 1:14 ` Rik van Riel
2012-08-16 1:17 ` Arjan van de Ven
2012-08-16 1:21 ` Arjan van de Ven
2012-08-15 14:19 ` Arjan van de Ven
2012-08-15 14:44 ` Peter Zijlstra
2012-08-15 14:47 ` Thomas Gleixner
2012-08-15 16:23 ` Matthew Garrett
2012-08-15 16:34 ` Matthew Garrett
2012-08-15 18:02 ` Arjan van de Ven
2012-08-17 8:59 ` Paul Turner
2012-08-16 3:07 ` Alex Shi
2012-08-16 6:53 ` preeti
2012-08-16 9:58 ` Alex Shi
2012-08-16 12:45 ` Shilimkar, Santosh
2012-08-16 14:01 ` Arjan van de Ven
2012-08-16 18:45 ` Rik van Riel
2012-08-16 19:20 ` Arjan van de Ven
2012-08-17 1:29 ` Alex Shi
2012-08-17 18:41 ` Matthew Garrett
2012-08-17 18:44 ` Arjan van de Ven
2012-08-17 18:47 ` Matthew Garrett
2012-08-17 19:45 ` Chris Friesen
2012-08-17 19:50 ` Matthew Garrett
2012-08-17 20:16 ` Chris Friesen
2012-08-18 14:33 ` Luming Yu
2012-08-18 14:52 ` Arjan van de Ven
2012-08-16 14:31 ` Morten Rasmussen
2012-08-19 10:12 ` Juri Lelli
2012-08-17 8:43 ` Paul Turner
2012-08-20 15:55 ` Vincent Guittot
2012-08-20 15:36 ` Vincent Guittot
2012-08-21 0:58 ` Alex Shi
2012-08-21 11:05 ` Vincent Guittot
2012-08-15 14:24 ` Rakib Mullick
2012-08-15 14:55 ` Peter Zijlstra
2012-08-15 22:58 ` Rakib Mullick
2012-08-16 5:26 ` Alex Shi
2012-08-16 4:57 ` Alex Shi
2012-08-16 8:05 ` Rakib Mullick
2012-08-15 16:19 ` Matthew Garrett
2012-08-16 5:03 ` Alex Shi
2012-08-16 5:31 ` Matthew Garrett
2012-08-16 5:39 ` Alex Shi
2012-08-16 5:45 ` Matthew Garrett
2012-08-16 13:57 ` Arjan van de Ven
2012-08-20 15:47 ` Christoph Lameter
2012-08-20 15:52 ` Matthew Garrett
2012-08-20 19:22 ` Christoph Lameter
2012-08-20 15:47 ` Vincent Guittot
2012-08-21 1:05 ` Alex Shi
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