Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751268AbWITHnC (ORCPT ); Wed, 20 Sep 2006 03:43:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751271AbWITHnB (ORCPT ); Wed, 20 Sep 2006 03:43:01 -0400 Received: from fbxmetz.linbox.com ([81.56.128.63]:63466 "EHLO fbxmetz.linbox.com") by vger.kernel.org with ESMTP id S1751268AbWITHnA (ORCPT ); Wed, 20 Sep 2006 03:43:00 -0400 Message-ID: <4510F0FD.4060602@linbox.com> Date: Wed, 20 Sep 2006 09:42:53 +0200 From: Ludovic Drolez User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20060628 Debian/1.7.8-1sarge7.1 X-Accept-Language: fr, en-us, en MIME-Version: 1.0 To: Antonio Vargas CC: linux-kernel@vger.kernel.org, subdino2004@yahoo.fr Subject: Re: [PATCH] sched.c: Be a bit more conservative in SMP References: <200609031541.39984.subdino2004@yahoo.fr> <200609031910.57259.vincent.plr@wanadoo.fr> <200609070130.53995.vincent.plr@wanadoo.fr> <69304d110609191050w777a5c48ibe84bc0e3ce65df3@mail.gmail.com> In-Reply-To: <69304d110609191050w777a5c48ibe84bc0e3ce65df3@mail.gmail.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1334 Lines: 41 Antonio Vargas wrote: > A variant on this theme would be (not tested or somewhat, just a > random idea for considering): > > 1. find if the process is a cpu-hog, if not then ignore > > 2. find somehow how much time has this process on it's current cpu > > 3. then, instead of always substracting 1 from th current load on the > current cpu, substract for example 1...0 when running from 0 to 60 > seconds... this way cpu hogs would only rotate slowly? > > in code: > > number_to_sub_from_queue_load = (256 - min(256, > time_from_last_change_of_cpu)) >> 8; > > somehow managing to get fixedpoint loadlevels on the runqueues would > make this work better.... > Yes ! That might be a better idea ! In fact, I tested the 1st patch on our cluster (Finite elements computing on 8 CPUs): - Under Windows: 875 seconds - Linux 2.6.16 : 1019 s - Linux 2.6.16 + manual taskset : 842 s - Linux 2.6.16 + Vincent's patch : 1373 s :-( If you find time to write a patch, Antonio, I would be pleased to try it ! Cheers, -- Ludovic DROLEZ http://lrs.linbox.org - Free asset management software - 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/