From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754266AbeBBR3w (ORCPT ); Fri, 2 Feb 2018 12:29:52 -0500 Received: from mout.gmx.net ([212.227.17.21]:63138 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753873AbeBBRTH (ORCPT ); Fri, 2 Feb 2018 12:19:07 -0500 Message-ID: <1517591925.8368.58.camel@gmx.de> Subject: Re: [RFC PATCH] sched/fair: Optionally restrict SMT scheduling ("restrict_smt") From: Mike Galbraith To: Sergio Lopez , linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org Date: Fri, 02 Feb 2018 18:18:45 +0100 In-Reply-To: <1517584441.10356.21.camel@sinrega.org> References: <20180201123748.32596-1-slp@sinrega.org> <1517495872.23787.20.camel@gmx.de> <1517584441.10356.21.camel@sinrega.org> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:qk34Jo//ilg6nUMq/XPbTXD3GiJUEWupdaQg0YgcRU2fmSrZbtW qw9QQt/M47tb9W4Yt9Fp5CpssBCG+Clqe5EMqOjVEPSPo8gnwB3/wBEvQ1vr5YhAgKY9LZQ z3jX66vYzl5mauBhpIYi2+9rHG8Dn0icoUsznGJMg5mtGgvPz261O1fYOV50CKsBKFwOsrP MeJzXD4XRZKjrDxXBU8hw== X-UI-Out-Filterresults: notjunk:1;V01:K0:qM/1mKpF7U8=:CUtAz17HmQbU4oiQkwk+eP sb7RknmHuJ+8tPqQ3ktRWvluJ5Oiom2HKVSoISnuaYnz4w7qH236iapkiN6RvUoIu5cIPUx0V OAPvQZuotYqz9MnnJLU8E8goDRxikhONakEhaM+WJzBvmNNyK0JXIoP3pRT6UZsCUxAE7Nik+ r0er2JIAroS2WzdRXeG50oJuxgAcamWdz+AP29npY6YaLAmoy5CfZw0JD8FeZA3oKenFWUGQO mQ9S4jzfm/9ITXsTPM2xY6dizm5QJZldS79JElwQB1IliLCUXZsUaFxA0EnWvC/wp51y5wUxV 1AImZCEeq6vGgIpdK7LwHg5jk9FFgNOIPcM8zJrvyWk7XesYU986XgbhqdqBnpZpGSMqrt8nS LJ5jvLwD6P3FgSFVZlZVGHrMoVpn/yOwt1u9mMgymcimLwHKaNy042stns38ZfNCn3n+ERb0I NdMab455ttJ/4mDf9jU+iLSWamSNmlakf/O95ZUOy770ua/MfWIi2mQoLkDmZOLJv2YbfCjKq BirnVXqmWiRLjH+Hg6PAh+n5+H61fut+BwCcHx5KczfwF4JxHRVccrHsJMZM7nua2mdjZR9ki SIt7CojpSwMSb4UvNKFAQ1HGkyYbgQX5e1BDBT03F6yIakg5feDiohtKYAcVsgLBFG54fTFML LcVj2RA5giupCwJ7mKlm57RIp4Wc2qBpZMPVTKM5qYG089naQ/265HaJQ5hnf4Zg/hijhqrur DroAf5hjdbNXxM8BtMd6Yp7Q6odFj2d7vBui7/V8TKDwVZyvlIWjYszuPsXvSKzb1EbG7Hmh3 tukjPCzxgomWEbrqyLqRFPip5CvGoKUvV50Bd6YBTkpkVxEAW4= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2018-02-02 at 16:14 +0100, Sergio Lopez wrote: > On Thu, 2018-02-01 at 15:37 +0100, Mike Galbraith wrote: > > On Thu, 2018-02-01 at 13:37 +0100, Sergio Lopez wrote: > > > Compared against "isolcpus", "restrict_smt" presents the following > > > advantages: > > > - Doesn't require prior knowledge of the CPU topology, making it > > > more friendly to both end users and automation tools. > > > - Load balancing is still active for tasks pinned to multiple > > > secondary SMT threads. > > > > This says that everybody and everything in the box is way smarter > > than the admin. > > If that's an argument in favor of manual pinning and isolation, I have > to disagree with you. That's an unnecessary burden put on the shoulders > of the admin. Give the admin job to one of those users you mentioned who knows which threads are "secondary" threads, he/she won't be burdened at all. -Mike