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Date: Fri, 17 Aug 2012 19:41:00 +0100
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: preeti <preeti@linux.vnet.ibm.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,
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        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
Message-ID: <20120817184100.GA13369@srcf.ucam.org>
References: <5028F12C.7080405@intel.com>
 <1345028738.31459.82.camel@twins>
 <502C98E8.20800@linux.vnet.ibm.com>
 <502CFD35.5000801@linux.intel.com>
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On Thu, Aug 16, 2012 at 07:01:25AM -0700, Arjan van de Ven wrote:
> > *Power policy*:
> > 
> > So how is power policy different? As Peter says,'pack more than spread
> > more'.
> 
> this is ... a dubiously general statement.
> 
> for good power, at least on Intel cpus, you want to spread. Parallelism is efficient.

Is this really true? In a two-socket system I'd have thought the benefit 
of keeping socket 1 in package C3 outweighed the cost of keeping socket 
0 awake for slightly longer.

-- 
Matthew Garrett | mjg59@srcf.ucam.org
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