Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423342Ab3FUPi7 (ORCPT ); Fri, 21 Jun 2013 11:38:59 -0400 Received: from mga14.intel.com ([143.182.124.37]:5997 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161419Ab3FUPi6 (ORCPT ); Fri, 21 Jun 2013 11:38:58 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,913,1363158000"; d="scan'208";a="353590885" Message-ID: <51C47377.2000208@linux.intel.com> Date: Fri, 21 Jun 2013 08:38:31 -0700 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Morten Rasmussen CC: David Lang , Ingo Molnar , "alex.shi@intel.com" , "peterz@infradead.org" , "preeti@linux.vnet.ibm.com" , "vincent.guittot@linaro.org" , "efault@gmx.de" , "pjt@google.com" , "linux-kernel@vger.kernel.org" , "linaro-kernel@lists.linaro.org" , "len.brown@intel.com" , "corbet@lwn.net" , Andrew Morton , Linus Torvalds , "tglx@linutronix.de" , Catalin Marinas Subject: Re: power-efficient scheduling design References: <20130530134718.GB32728@e103034-lin> <20130531105204.GE30394@gmail.com> <20130614160522.GG32728@e103034-lin> <51C07ABC.2080704@linux.intel.com> <51C1D0BB.3040705@linux.intel.com> <20130619170042.GH5460@e103034-lin> <51C1E58D.9000408@linux.intel.com> <20130621085002.GJ5460@e103034-lin> In-Reply-To: <20130621085002.GJ5460@e103034-lin> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 951 Lines: 19 On 6/21/2013 1:50 AM, Morten Rasmussen wrote: >> ypically. > A hint when a task is moved to a new cpu is too late if the migration > shouldn't have happened at all. If the scheduler knows that the cpu is > able to switch to a higher p-state it can decide to wait for the p-state > change instead of migrating the task and waking up another cpu. > oops sorry I misread your mail (lack of early coffee I suppose) I can see your point of having a thing for "did we ask for all the performance we could ask for" prior to doing a load balance (although, for power efficiency, if you have two tasks that could run in parallel, it's usually better to run them in parallel... so likely we should balance anyway) -- 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/