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=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 B8C92C433E6 for ; Wed, 24 Feb 2021 18:48:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7580A64FE8 for ; Wed, 24 Feb 2021 18:48:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235175AbhBXSr7 (ORCPT ); Wed, 24 Feb 2021 13:47:59 -0500 Received: from foss.arm.com ([217.140.110.172]:44212 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234634AbhBXSrN (ORCPT ); Wed, 24 Feb 2021 13:47:13 -0500 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 14FE9D6E; Wed, 24 Feb 2021 10:46:28 -0800 (PST) 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 314433F73B; Wed, 24 Feb 2021 10:46:26 -0800 (PST) From: Valentin Schneider To: Vincent Guittot , mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, linux-kernel@vger.kernel.org, joel@joelfernandes.org Cc: fweisbec@gmail.com, tglx@linutronix.de, qais.yousef@arm.com, Vincent Guittot Subject: Re: [PATCH 0/7 v4] move update blocked load outside newidle_balance In-Reply-To: <20210224133007.28644-1-vincent.guittot@linaro.org> References: <20210224133007.28644-1-vincent.guittot@linaro.org> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/26.3 (x86_64-pc-linux-gnu) Date: Wed, 24 Feb 2021 18:46:23 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/02/21 14:30, Vincent Guittot wrote: > Joel reported long preempt and irq off sequence in newidle_balance because > of a large number of CPU cgroups in use and having to be updated. This > patchset moves the update outside newidle_imblance. This enables to early > abort during the updates in case of pending irq as an example. > > Instead of kicking a normal ILB that will wakes up CPU which is already > idle, patch 6 triggers the update of statistics in the idle thread of > the CPU before selecting and entering an idle state. > > Changes on v4: > - Add a dedicated bit for updating blocked load when entering idle. > This simplifies the management of concurrency with kick_ilb. > I believe that solves the issues vs nohz balance. One last thing for patch 7: mayhaps we could do a tad better to avoid duplicate updates going through a heapful of leaf cfs rqs, see http://lore.kernel.org/r/jhj4kiht7oh.mognet@arm.com Otherwise, feel free to add to the lot: Reviewed-by: Valentin Schneider