From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933388AbeBUKj7 (ORCPT ); Wed, 21 Feb 2018 05:39:59 -0500 Received: from terminus.zytor.com ([198.137.202.136]:39271 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932751AbeBUKj4 (ORCPT ); Wed, 21 Feb 2018 05:39:56 -0500 Date: Wed, 21 Feb 2018 02:38:21 -0800 From: tip-bot for Frederic Weisbecker Message-ID: Cc: frederic@kernel.org, riel@redhat.com, cmetcalf@mellanox.com, torvalds@linux-foundation.org, cl@linux.com, paulmck@linux.vnet.ibm.com, kernellwp@gmail.com, mingo@kernel.org, linux-kernel@vger.kernel.org, lcapitulino@redhat.com, tglx@linutronix.de, hpa@zytor.com, peterz@infradead.org, efault@gmx.de Reply-To: linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, lcapitulino@redhat.com, mingo@kernel.org, kernellwp@gmail.com, efault@gmx.de, riel@redhat.com, cmetcalf@mellanox.com, frederic@kernel.org, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org, cl@linux.com In-Reply-To: <1519186649-3242-8-git-send-email-frederic@kernel.org> References: <1519186649-3242-8-git-send-email-frederic@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/isolation: Update nohz documentation to explain tick offload Git-Commit-ID: 083c6eeab2cc13894618d188b854f2fc6b5b2303 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 083c6eeab2cc13894618d188b854f2fc6b5b2303 Gitweb: https://git.kernel.org/tip/083c6eeab2cc13894618d188b854f2fc6b5b2303 Author: Frederic Weisbecker AuthorDate: Wed, 21 Feb 2018 05:17:29 +0100 Committer: Ingo Molnar CommitDate: Wed, 21 Feb 2018 09:49:10 +0100 sched/isolation: Update nohz documentation to explain tick offload Update the documentation to reflect the 1Hz tick offload changes. Signed-off-by: Frederic Weisbecker Reviewed-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: Chris Metcalf Cc: Christoph Lameter Cc: Linus Torvalds Cc: Luiz Capitulino Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Rik van Riel Cc: Wanpeng Li Link: http://lkml.kernel.org/r/1519186649-3242-8-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar --- Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1d1d53f..50b9837 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1766,6 +1766,17 @@ nohz Disable the tick when a single task runs. + + A residual 1Hz tick is offloaded to workqueues, which you + need to affine to housekeeping through the global + workqueue's affinity configured via the + /sys/devices/virtual/workqueue/cpumask sysfs file, or + by using the 'domain' flag described below. + + NOTE: by default the global workqueue runs on all CPUs, + so to protect individual CPUs the 'cpumask' file has to + be configured manually after bootup. + domain Isolate from the general SMP balancing and scheduling algorithms. Note that performing domain isolation this way