From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753362AbZENO7o (ORCPT ); Thu, 14 May 2009 10:59:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751600AbZENO7e (ORCPT ); Thu, 14 May 2009 10:59:34 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:36805 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751010AbZENO7e (ORCPT ); Thu, 14 May 2009 10:59:34 -0400 Date: Thu, 14 May 2009 20:28:29 +0530 From: Vaidyanathan Srinivasan To: Andi Kleen Cc: Peter Zijlstra , Linux Kernel , Suresh B Siddha , Venkatesh Pallipadi , Arjan van de Ven , Ingo Molnar , Dipankar Sarma , Balbir Singh , Vatsa , Gautham R Shenoy , Gregory Haskins , Mike Galbraith , Thomas Gleixner , Arun Bharadwaj Subject: Re: [RFC PATCH v2 0/2] Saving power by cpu evacuation sched_max_capacity_pct=n Message-ID: <20090514145045.GH4853@dirshya.in.ibm.com> Reply-To: svaidy@linux.vnet.ibm.com References: <20090513130541.21440.33364.stgit@drishya.in.ibm.com> <20090513143550.GU19296@one.firstfloor.org> <1242225402.26820.23.camel@twins> <20090513144659.GV19296@one.firstfloor.org> <1242226219.26820.26.camel@twins> <20090513150100.GW19296@one.firstfloor.org> <1242226927.26820.30.camel@twins> <20090513151054.GY19296@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090513151054.GY19296@one.firstfloor.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen [2009-05-13 17:10:54]: > > > Yes that's fine and common, but you actually need to save power for this, > > > which throttling doesn't do. > > > > > > My understanding this work is a extension of the existing > > > sched_mc_power_savings features that tries to be optionally more > > > aggressive to keep complete package idle so that package level > > > power saving kicks in. > > > > > > I'm just requesting that they don't call that throttling. > > > > Ah no, this work differs in that regard in that it actually 'generates' > > idle time, instead of optimizing idle time. > > That is what i meant with "more aggressive to keep complete packages idle" > above. Hi Andi, There is a difference in the framework as Peter has mentioned, we are trying to create idle times by forcefully reducing work. From an end-user point of view, this can be seen as a logical extension of sched_mc_power_savings... v1 of the RFC extends the framework. However Ingo suggested that the knob is not intuitive and hence I have tried to switch to a percentage knob sched_max_capacity_pct. I am interested in an easy, simple and intuitive framework to evacuate cores which may imply forcefully reducing (throttling) work. > > Therefore it takes actual cpu time away from real work, which is > > throttling. Granted, one could call it limiting or similar, but > > throttling is a correct name. > > That will be always ongoing confusion with the existing established > term. > > If you really need to call it throttling use "scheduler throttling" > or something like that, but a different word would be better. I think 'scheduler throttling' is good so that we avoid the term 'CPU throttling' or core throttling. I had named this cpu evacuation or core evacuation just to avoid confusion with hardware throttling. --Vaidy