Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755970Ab2HQBaH (ORCPT ); Thu, 16 Aug 2012 21:30:07 -0400 Received: from mga11.intel.com ([192.55.52.93]:43598 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752688Ab2HQBaF (ORCPT ); Thu, 16 Aug 2012 21:30:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,782,1336374000"; d="scan'208";a="203168962" Message-ID: <502D9E78.5010403@intel.com> Date: Fri, 17 Aug 2012 09:29:28 +0800 From: Alex Shi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111229 Thunderbird/9.0 MIME-Version: 1.0 To: Arjan van de Ven CC: preeti , Peter Zijlstra , 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> In-Reply-To: <502CFD35.5000801@linux.intel.com> 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: 935 Lines: 30 On 08/16/2012 10:01 PM, 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. > > the only thing you do not want to do, is wake cpus up for > tasks that only run extremely briefly (think "100 usec" or less). It's a very important and valuable info! Just want to know how you get this? From CS cost or cache/TLB refill cost? > > so maybe the balance interval is slightly different, or more, you don't balance tasks that > historically ran only for brief periods > > -- 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/