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=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1, USER_IN_DEF_DKIM_WL 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 86626C64E69 for ; Mon, 23 Nov 2020 12:32:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F6F020728 for ; Mon, 23 Nov 2020 12:32:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Ol3EZTG0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731039AbgKWMcO (ORCPT ); Mon, 23 Nov 2020 07:32:14 -0500 Received: from linux.microsoft.com ([13.77.154.182]:46766 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730882AbgKWMbi (ORCPT ); Mon, 23 Nov 2020 07:31:38 -0500 Received: from [192.168.86.179] (c-73-38-52-84.hsd1.vt.comcast.net [73.38.52.84]) by linux.microsoft.com (Postfix) with ESMTPSA id 8231420B717A; Mon, 23 Nov 2020 04:31:32 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 8231420B717A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1606134697; bh=AnLY0dO2FA+3o6DtA4/k5Dy8gSbI6WdqCxQNTo/PGeg=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Ol3EZTG0iYy+uTvwrQazqr5gw6atBDLa/copkjN3MVYaM6My8pDN85RxPKO5XG48/ 9ODHKxwKpVlt3m7CaNVvJjrK4O2Ll1hzlrcHyFpRTH8myusv3sRs40ErugiV6SyS9d Q86ZiZ48wtTw2Z91jnEAsPIJsdRa+iFUz7Bjytbs= Subject: Re: [PATCH -tip 09/32] sched/fair: Snapshot the min_vruntime of CPUs on force idle To: Balbir Singh , "Joel Fernandes (Google)" Cc: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , Tim Chen , Aaron Lu , Aubrey Li , tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, torvalds@linux-foundation.org, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Phil Auld , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , vineeth@bitbyteword.org, Chen Yu , Christian Brauner , Agata Gruza , Antonio Gomez Iglesias , graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com, pjt@google.com, rostedt@goodmis.org, derkling@google.com, benbjiang@tencent.com, Alexandre Chartre , James.Bottomley@hansenpartnership.com, OWeisse@umich.edu, Dhaval Giani , Junaid Shahid , jsbarnes@google.com, chris.hyser@oracle.com, Ben Segall , Josh Don , Hao Luo , Tom Lendacky , Aubrey Li , "Paul E. McKenney" , Tim Chen References: <20201117232003.3580179-1-joel@joelfernandes.org> <20201117232003.3580179-10-joel@joelfernandes.org> <20201122114442.GD110669@balbir-desktop> From: Vineeth Pillai Message-ID: <2cb42831-5074-e0a9-9e2a-f2a880504026@linux.microsoft.com> Date: Mon, 23 Nov 2020 07:31:31 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.2 MIME-Version: 1.0 In-Reply-To: <20201122114442.GD110669@balbir-desktop> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Balbir, On 11/22/20 6:44 AM, Balbir Singh wrote: > > This seems cumbersome, is there no way to track the min_vruntime via > rq->core->min_vruntime? Do you mean to have a core wide min_vruntime? We had a similar approach from v3 to v7 and it had major issues which broke the assumptions of cfs. There were some lengthy discussions and Peter explained in-depth about the issues: https://lwn.net/ml/linux-kernel/20200506143506.GH5298@hirez.programming.kicks-ass.net/ https://lwn.net/ml/linux-kernel/20200515103844.GG2978@hirez.programming.kicks-ass.net/ Thanks, Vineeth