From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH v4 2/2] cpusets,isolcpus: add file to show isolated cpus in cpuset Date: Tue, 3 Mar 2015 17:51:27 +0800 Message-ID: <54F5841F.3020402@huawei.com> References: <1424882288-2910-1-git-send-email-riel@redhat.com> <1424882288-2910-3-git-send-email-riel@redhat.com> <54EEFE15.3010005@huawei.com> <20150226121231.6fcba7e8@annuminas.surriel.com> <54F4000B.5000901@huawei.com> <20150302091213.GI21418@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150302091213.GI21418@twins.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Peter Zijlstra Cc: Rik van Riel , linux-kernel@vger.kernel.org, Clark Williams , Ingo Molnar , Luiz Capitulino , David Rientjes , Mike Galbraith , cgroups@vger.kernel.org On 2015/3/2 17:12, Peter Zijlstra wrote: > On Mon, Mar 02, 2015 at 02:15:39PM +0800, Zefan Li wrote: >> Hi Rik, >> >>> Subject: cpusets,isolcpus: add file to show isolated cpus in cpuset >>> >>> The previous patch makes it so the code skips over isolcpus when >>> building scheduler load balancing domains. This makes it hard to >>> see for a user which of the CPUs in a cpuset are participating in >>> load balancing, and which ones are isolated cpus. >>> >>> Add a cpuset.isolcpus file with info on which cpus in a cpuset are >>> isolated CPUs. >>> >>> This file is read-only for now. In the future we could extend things >>> so isolcpus can be changed at run time, for the root (system wide) >>> cpuset only. >>> >> >> One Question, why not add a /sys/devices/system/cpu/isolated instead? > > It would leave userspace to calculate the result for any one cpuset > itself. It's trivial. Instead of reading cpuset.isolcpus, now we read cpuset.cpus and /sys/.../isolated. > Furthermore, is that /sys thing visible for all nested > containers? > . > Never tried nested containers, but I think so. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932078AbbCCJzE (ORCPT ); Tue, 3 Mar 2015 04:55:04 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:15985 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756088AbbCCJy5 (ORCPT ); Tue, 3 Mar 2015 04:54:57 -0500 Message-ID: <54F5841F.3020402@huawei.com> Date: Tue, 3 Mar 2015 17:51:27 +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: Peter Zijlstra CC: Rik van Riel , , "Clark Williams" , Ingo Molnar , "Luiz Capitulino" , David Rientjes , Mike Galbraith , Subject: Re: [PATCH v4 2/2] cpusets,isolcpus: add file to show isolated cpus in cpuset References: <1424882288-2910-1-git-send-email-riel@redhat.com> <1424882288-2910-3-git-send-email-riel@redhat.com> <54EEFE15.3010005@huawei.com> <20150226121231.6fcba7e8@annuminas.surriel.com> <54F4000B.5000901@huawei.com> <20150302091213.GI21418@twins.programming.kicks-ass.net> In-Reply-To: <20150302091213.GI21418@twins.programming.kicks-ass.net> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset="ISO-8859-1" 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 On 2015/3/2 17:12, Peter Zijlstra wrote: > On Mon, Mar 02, 2015 at 02:15:39PM +0800, Zefan Li wrote: >> Hi Rik, >> >>> Subject: cpusets,isolcpus: add file to show isolated cpus in cpuset >>> >>> The previous patch makes it so the code skips over isolcpus when >>> building scheduler load balancing domains. This makes it hard to >>> see for a user which of the CPUs in a cpuset are participating in >>> load balancing, and which ones are isolated cpus. >>> >>> Add a cpuset.isolcpus file with info on which cpus in a cpuset are >>> isolated CPUs. >>> >>> This file is read-only for now. In the future we could extend things >>> so isolcpus can be changed at run time, for the root (system wide) >>> cpuset only. >>> >> >> One Question, why not add a /sys/devices/system/cpu/isolated instead? > > It would leave userspace to calculate the result for any one cpuset > itself. It's trivial. Instead of reading cpuset.isolcpus, now we read cpuset.cpus and /sys/.../isolated. > Furthermore, is that /sys thing visible for all nested > containers? > . > Never tried nested containers, but I think so.