From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92A5FC433E0 for ; Thu, 11 Jun 2020 14:12:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7749220842 for ; Thu, 11 Jun 2020 14:12:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728193AbgFKOMQ (ORCPT ); Thu, 11 Jun 2020 10:12:16 -0400 Received: from foss.arm.com ([217.140.110.172]:53144 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726808AbgFKOMQ (ORCPT ); Thu, 11 Jun 2020 10:12:16 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C331A1F1; Thu, 11 Jun 2020 07:12:15 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4E3803F6CF; Thu, 11 Jun 2020 07:12:14 -0700 (PDT) References: <20200609123748.18636-1-vincent.guittot@linaro.org> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Vincent Guittot Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org, iwtbavbm@gmail.com Subject: Re: [PATCH v2] sched/fair: fix nohz next idle balance In-reply-to: <20200609123748.18636-1-vincent.guittot@linaro.org> Date: Thu, 11 Jun 2020 15:12:11 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/06/20 13:37, Vincent Guittot wrote: > With commit: > 'b7031a02ec75 ("sched/fair: Add NOHZ_STATS_KICK")' > rebalance_domains of the local cfs_rq happens before others idle cpus have > updated nohz.next_balance and its value is overwritten. > > Move the update of nohz.next_balance for other idles cpus before balancing > and updating the next_balance of local cfs_rq. > > Also, the nohz.next_balance is now updated only if all idle cpus got a > chance to rebalance their domains and the idle balance has not been aborted > because of new activities on the CPU. In case of need_resched, the idle > load balance will be kick the next jiffie in order to address remaining > ilb. > > Reported-by: Peng Liu > Signed-off-by: Vincent Guittot FWIW: Reviewed-by: Valentin Schneider Do we want a Fixes: tag for this? I'm thinking b7031a02ec75 ("sched/fair: Add NOHZ_STATS_KICK")