From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [PATCH v4 2/2] cpusets,isolcpus: add file to show isolated cpus in cpuset Date: Mon, 02 Mar 2015 15:54:49 +0100 Message-ID: <1425308089.2859.7.camel@gmail.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> <20150302090933.GH21418@twins.programming.kicks-ass.net> <1425300290.5863.17.camel@gmail.com> <54F47534.7070204@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:subject:from:to:cc:date:in-reply-to:references :content-type:mime-version:content-transfer-encoding; bh=LMdJ2m3kYrygmCi7u+F48U5Xi2GY0twQblmkAYokmEM=; b=c5TEKXTiqjsUTS5cP36z4ISB1cUKV25C1AuJAXszqPxP4MoQXWNrXkK//iYkG0CsO1 j+c5ZXpX4HYRhmgkxhLGmPxqZh3M6BteAkK+bmVzv0r0zJckLxrq4jQQFGM027qpm2UG O2qpLcd57aJQtwCvxSBl0lFwad+XCDi7AYSS8B8XsrRqBh0f/ZBW8j4K3oWJMwYIqwxT e2pEjMphm/RR+ev/9MWyG8jWJ0WCsMxO64DjKEqMd4vdw7hwO2amieSLMsfV/hvS8fAC 0MM5H7LGSeDs3ImlXR7Rh28a+X82FPENsaKvA3LjBnsXfoUwItlKf2kbh2f62YdMJCv0 QP5A== In-Reply-To: <54F47534.7070204-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Rik van Riel Cc: Peter Zijlstra , Zefan Li , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Clark Williams , Ingo Molnar , Luiz Capitulino , David Rientjes , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Mon, 2015-03-02 at 09:35 -0500, Rik van Riel wrote: > On 03/02/2015 07:44 AM, Mike Galbraith wrote: > > On Mon, 2015-03-02 at 10:09 +0100, Peter Zijlstra wrote: > >> On Thu, Feb 26, 2015 at 12:12:31PM -0500, Rik van Riel wrote: > >>> 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. > >>> > >>> Acked-by: David Rientjes > >>> Cc: Peter Zijlstra > >>> Cc: Clark Williams > >>> Cc: Li Zefan > >>> Cc: Ingo Molnar > >>> Cc: Luiz Capitulino > >>> Cc: David Rientjes > >>> Cc: Mike Galbraith > >>> Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > >>> Signed-off-by: Rik van Riel > >> > >> So let me start off by saying I hate isolcpus ;-) > >> > >> Let me further state that I had hopes we could extend cpusets to > >> natively provide the functionality isolcpus has, and kill isolcpus. > > > > +1 > > > > That's where nohz_full goop belongs too. > > Except nohz_full and isolcpus are very much global attributes of > each CPU, so I am not sure whether it would make sense to allow > configuration of this attribute anywhere other than the root > cpuset. They're attributes of exclusive sets, which excludes the root set. It'd be kinda hard to have the root set be both ticked and tickless :) -Mike