Message-ID: <1345614110.4374.65.camel@marge.simpson.net>
Subject: Re: [discussion]sched: a rough proposal to enable power saving in
 scheduler
From: Mike Galbraith <efault@gmx.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>, Matthew Garrett <mjg59@srcf.ucam.org>,
        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>
Date: Wed, 22 Aug 2012 07:41:50 +0200
In-Reply-To: <20120821170254.0b10ece6@pyramind.ukuu.org.uk>
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On Tue, 2012-08-21 at 17:02 +0100, Alan Cox wrote:

> I'd like to see actual numbers and evidence on a wide range of workloads
> the spread/don't spread thing is even measurable given that you've also
> got to factor in effects like completing faster and turning everything
> off. I'd *really* like to see such evidence on a laptop,which is your
> one cited case it might work.

For my dinky dual core laptop, I suspect you're right, but for a more
powerful laptop, I'd expect spread/don't to be noticeable.

Yeah, hard numbers would be nice to see.

If I had a powerful laptop, I'd kill irq balancing, and all but periodic
load balancing, and expect to see a positive result.  Dunno what fickle
electron gods would _really_ do with those prayers though.

-Mike

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