From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753844AbbCaVGl (ORCPT ); Tue, 31 Mar 2015 17:06:41 -0400 Received: from mail-qg0-f42.google.com ([209.85.192.42]:36153 "EHLO mail-qg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751774AbbCaVGk (ORCPT ); Tue, 31 Mar 2015 17:06:40 -0400 Date: Tue, 31 Mar 2015 17:06:36 -0400 From: Tejun Heo To: Frederic Weisbecker Cc: cmetcalf@ezchip.com, "Peter Zijlstra (Intel)" , "Paul E. McKenney" , "Rafael J. Wysocki" , Martin Schwidefsky , linux-kernel@vger.kernel.org Subject: Re: [PATCH] workqueue: avoid nohz_full cores Message-ID: <20150331210636.GJ9974@htj.duckdns.org> References: <1427829959-3023-1-git-send-email-cmetcalf@ezchip.com> <20150331205839.GA32112@lerouge> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150331205839.GA32112@lerouge> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 31, 2015 at 10:58:41PM +0200, Frederic Weisbecker wrote: > On Tue, Mar 31, 2015 at 03:25:59PM -0400, cmetcalf@ezchip.com wrote: > > From: Chris Metcalf > > > > When queuing work, we should avoid queuing it on the local cpu if > > we are using WORK_CPU_UNBOUND and the local cpu is nohz_full, since > > the workqueue will mean a later interrupt of the nohz_full process > > that presumably would prefer continuing to have 100% of the core > > without interrupts. > > > > Likewise, remove the nohz_full cores from unbound workqueues. If > > all the cores are nohz_full, we leave them in. > > > > Signed-off-by: Chris Metcalf > > Lai is already working on this: https://lkml.org/lkml/2015/3/12/27 > > All that will be needed after this patchset is to force the desired > unbound workqueue mask on boot. This applies to per-cpu workqueues too, not just unbound workqueues. Thanks. -- tejun