Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758828Ab2HQSoV (ORCPT ); Fri, 17 Aug 2012 14:44:21 -0400 Received: from mga11.intel.com ([192.55.52.93]:65488 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757598Ab2HQSoN (ORCPT ); Fri, 17 Aug 2012 14:44:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,785,1336374000"; d="scan'208";a="210008597" Message-ID: <502E90F3.2000702@linux.intel.com> Date: Fri, 17 Aug 2012 11:44:03 -0700 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20120713 Thunderbird/14.0 MIME-Version: 1.0 To: Matthew Garrett CC: preeti , Peter Zijlstra , Alex Shi , Suresh Siddha , vincent.guittot@linaro.org, svaidy@linux.vnet.ibm.com, Ingo Molnar , Andrew Morton , Linus Torvalds , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Paul Turner Subject: Re: [discussion]sched: a rough proposal to enable power saving in scheduler References: <5028F12C.7080405@intel.com> <1345028738.31459.82.camel@twins> <502C98E8.20800@linux.vnet.ibm.com> <502CFD35.5000801@linux.intel.com> <20120817184100.GA13369@srcf.ucam.org> In-Reply-To: <20120817184100.GA13369@srcf.ucam.org> X-Enigmail-Version: 1.4.3 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 25 On 8/17/2012 11:41 AM, Matthew Garrett wrote: > 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. not on Intel you can't enter package c3 either until every one is down. (e.g. memory controller must stay on etc etc) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/