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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 3F5A0C2BA19 for ; Tue, 14 Apr 2020 14:29:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18E372064A for ; Tue, 14 Apr 2020 14:29:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390903AbgDNO3Z (ORCPT ); Tue, 14 Apr 2020 10:29:25 -0400 Received: from foss.arm.com ([217.140.110.172]:56948 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390563AbgDNO3E (ORCPT ); Tue, 14 Apr 2020 10:29:04 -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 31C7731B; Tue, 14 Apr 2020 07:29:04 -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 349573F73D; Tue, 14 Apr 2020 07:29:02 -0700 (PDT) References: <20200408095012.3819-1-dietmar.eggemann@arm.com> <20200408095012.3819-3-dietmar.eggemann@arm.com> <20200408153032.447e098d@nowhere> <31620965-e1e7-6854-ad46-8192ee4b41af@arm.com> <20200414114032.wigdlnegism6qqns@e107158-lin.cambridge.arm.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Qais Yousef Cc: Dietmar Eggemann , luca abeni , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Daniel Bristot de Oliveira , Wei Wang , Quentin Perret , Alessio Balsini , Pavan Kondeti , Patrick Bellasi , Morten Rasmussen , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] sched/deadline: Improve admission control for asymmetric CPU capacities In-reply-to: <20200414114032.wigdlnegism6qqns@e107158-lin.cambridge.arm.com> Date: Tue, 14 Apr 2020 15:29:00 +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 14/04/20 12:40, Qais Yousef wrote: > > I haven't followed this discussion closely, so I could be missing something > here. > > In sched_cpu_dying() we call set_rq_offline() which clears the cpu in > rq->rd->online. > > So the way I read the code > > rd->online = cpumask_and(rd->span, cpu_active_mask) > > But I could have easily missed some detail. > sched_cpu_dying() is wayyyy below sched_cpu_deactivate(). This doesn't help at all for the dl_cpu_busy() check in sched_cpu_deactivate(). > Regardless, it seems to me that DL is working around something not right in the > definition of rd->span or using the wrong variable. > What DL is doing now is fine, it only needs to be aligned with the active mask (which it is). We're making things a bit trickier by adding capacity values into the mix. > My 2p :-). I have to go back and read the discussion in more detail. > > Thanks