Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbbB1DV5 (ORCPT ); Fri, 27 Feb 2015 22:21:57 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:17044 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752499AbbB1DVz (ORCPT ); Fri, 27 Feb 2015 22:21:55 -0500 Message-ID: <54F13446.8090808@huawei.com> Date: Sat, 28 Feb 2015 11:21:42 +0800 From: Zefan Li User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: CC: , Peter Zijlstra , Clark Williams , Ingo Molnar , "Luiz Capitulino" , Mike Galbraith , Subject: Re: [PATCH 1/2] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets References: <1424882288-2910-1-git-send-email-riel@redhat.com> <1424882288-2910-2-git-send-email-riel@redhat.com> In-Reply-To: <1424882288-2910-2-git-send-email-riel@redhat.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1532 Lines: 36 On 2015/2/26 0:38, riel@redhat.com wrote: > From: Rik van Riel > > Ensure that cpus specified with the isolcpus= boot commandline > option stay outside of the load balancing in the kernel scheduler. > > Operations like load balancing can introduce unwanted latencies, > which is exactly what the isolcpus= commandline is there to prevent. > > Previously, simply creating a new cpuset, without even touching the > cpuset.cpus field inside the new cpuset, would undo the effects of > isolcpus=, by creating a scheduler domain spanning the whole system, > and setting up load balancing inside that domain. The cpuset root > cpuset.cpus file is read-only, so there was not even a way to undo > that effect. > > This does not impact the majority of cpusets users, since isolcpus= > is a fairly specialized feature used for realtime purposes. > > Cc: Peter Zijlstra > Cc: Clark Williams > Cc: Li Zefan > Cc: Ingo Molnar > Cc: Luiz Capitulino > Cc: Mike Galbraith > Cc: cgroups@vger.kernel.org > Signed-off-by: Rik van Riel > Tested-by: David Rientjes Acked-by: Zefan Li -- 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/