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 C3AC4C4332D for ; Thu, 19 Mar 2020 12:07:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A35C920663 for ; Thu, 19 Mar 2020 12:07:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727112AbgCSMHM (ORCPT ); Thu, 19 Mar 2020 08:07:12 -0400 Received: from foss.arm.com ([217.140.110.172]:34092 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgCSMHM (ORCPT ); Thu, 19 Mar 2020 08:07:12 -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 846EE31B; Thu, 19 Mar 2020 05:07:11 -0700 (PDT) Received: from e113632-lin (unknown [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BAB883F305; Thu, 19 Mar 2020 05:07:10 -0700 (PDT) References: <20200311181601.18314-1-valentin.schneider@arm.com> <20200311181601.18314-9-valentin.schneider@arm.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Dietmar Eggemann Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org Subject: Re: [PATCH v2 8/9] sched/fair: Split select_task_rq_fair want_affine logic In-reply-to: Date: Thu, 19 Mar 2020 12:06:48 +0000 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 Thu, Mar 19 2020, Dietmar Eggemann wrote: >> + */ >> for_each_domain(cpu, tmp) { >> - /* >> - * If both 'cpu' and 'prev_cpu' are part of this domain, >> - * cpu is a valid SD_WAKE_AFFINE target. >> - */ >> - if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && >> + if ((tmp->flags & SD_WAKE_AFFINE) && >> cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { >> if (cpu != prev_cpu) >> new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync); >> >> - sd = NULL; /* Prefer wake_affine over balance flags */ >> + /* Prefer wake_affine over SD lookup */ > > I assume that 'balance flags' stands for (wakeup) load balance, i.e. > find_idlest_xxx() path. So why change it? > > You mean the comment part, right? I was hoping to clarify it a bit - if we go through the want_affine condition, we'll override whatever SD we picked with the highest_flag_domain() lookup (and the cached version in 9/9). Hence me referring to the SD lookup there. > [...]