Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750791AbWJQTEh (ORCPT ); Tue, 17 Oct 2006 15:04:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751421AbWJQTEh (ORCPT ); Tue, 17 Oct 2006 15:04:37 -0400 Received: from mga09.intel.com ([134.134.136.24]:9020 "EHLO mga09.intel.com") by vger.kernel.org with ESMTP id S1750791AbWJQTEg (ORCPT ); Tue, 17 Oct 2006 15:04:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: i="4.09,321,1157353200"; d="scan'208"; a="146458412:sNHT20221747" Date: Tue, 17 Oct 2006 11:43:06 -0700 From: "Siddha, Suresh B" To: Paul Jackson Cc: Dinakar Guniguntala , "Siddha, Suresh B" , Paul Menage , Simon.Derr@bull.net, linux-kernel@vger.kernel.org, Martin Bligh , Rohit Seth , dipankar@in.ibm.com Subject: Re: [RFC] Cpuset: explicit dynamic sched domain control flags Message-ID: <20061017114306.A19690@unix-os.sc.intel.com> References: <20061016230351.19049.29855.sendpatchset@jackhammer.engr.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20061016230351.19049.29855.sendpatchset@jackhammer.engr.sgi.com>; from pj@sgi.com on Mon, Oct 16, 2006 at 04:03:51PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 43 On Mon, Oct 16, 2006 at 04:03:51PM -0700, Paul Jackson wrote: > From: Paul Jackson > > I should get agreement from the other folks who care about the > interaction of cpusets and sched domains before submitting this > to Andrew for staging in *-mm. Your post actually reminds me that sched domain setup for exclusive cpusets are broken in the presence of cpu hotplug. That perhaps is a different context and will kick a different thread with interested parties. > In particular, I remain unsure of myself around the sched domain > code, and could use some feedback from someone with more of a > clue on whether I broke something here. I am not familiar with how job manager uses the cpusets but the current meaning/usage of 'cpu_exclusive' seems logical to me. Your current proposal seems to be wrong and broken. What your patch does is to have overlapping cpusets, lets take for example 2 cpusets and one cpuset with sched domain and another with no sched domain. All is fine(from cpu scheduler perspective) when the cpuset with sched domain is active and the job in cpuset with no sched domain is inactive. What happens when the job in the cpuset with no sched domain becomes active? In this case, scheduler can't make use of all cpus that this cpuset is allowed to use. This is because schedule domains in the system are paritioned based on the cpusets which define sched domain. cpus allowed for this cpuset(which doesnt define sched domain) may be spread across multiple sched domain partitions and scheduling doesn't happen across domain partitions. thanks, suresh - 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/