From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753471Ab3AaIZL (ORCPT ); Thu, 31 Jan 2013 03:25:11 -0500 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:48154 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954Ab3AaIZI (ORCPT ); Thu, 31 Jan 2013 03:25:08 -0500 Message-ID: <510A2A50.1090207@linux.vnet.ibm.com> Date: Thu, 31 Jan 2013 16:24:48 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Namhyung Kim CC: Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Ingo Molnar , Peter Zijlstra , tglx@linutronix.de Subject: Re: [RFC 2/2] sched/fair: prefer a CPU in the "lowest" idle state References: <1359580757-4121-1-git-send-email-bigeasy@linutronix.de> <1359580757-4121-3-git-send-email-bigeasy@linutronix.de> <5109D313.1020409@linux.vnet.ibm.com> <8738xiue31.fsf@sejong.aot.lge.com> <510A1198.2070803@linux.vnet.ibm.com> <87txpxu9cx.fsf@sejong.aot.lge.com> <510A1D7A.3050408@linux.vnet.ibm.com> <87pq0lu7ew.fsf@sejong.aot.lge.com> In-Reply-To: <87pq0lu7ew.fsf@sejong.aot.lge.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13013108-5816-0000-0000-0000067E4C75 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/31/2013 03:40 PM, Namhyung Kim wrote: > On Thu, 31 Jan 2013 15:30:02 +0800, Michael Wang wrote: >> On 01/31/2013 02:58 PM, Namhyung Kim wrote: >>> But AFAIK the number of states in cpuidle is usually less than 10 so maybe >>> we can change the weight then, but there's no promise... >> >> And I just got another case we should take care: >> >> group 0 cpu 0 cpu 1 >> power index 8 power index 8 >> >> >> group 1 cpu 2 cpu 3 >> power index 0 load 15 >> >> so load of group 0 is 16 and group 1 is 15, but group 0 is better... > > Maybe it's not. The cpus in group 0 are in a lower power state so that > there will be a benefit to select cpu 2 from the power' PoV IMHO. Also > such a low power state has a longer exit latency so that we should > choose cpu2 to get a better performance and it's the basic idea of this > patchset I believe. Well, this case is just to notify that, we may face the comparison between load and index, not between index and index, I just doubt there won't be a rule which could take care both, besides, comparison between load and index is strange... Regards, Michael Wang > > Thanks, > Namhyung > -- > 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/ >