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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 5BF79C433DF for ; Fri, 31 Jul 2020 19:21:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 492B0208E4 for ; Fri, 31 Jul 2020 19:21:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730201AbgGaTVA (ORCPT ); Fri, 31 Jul 2020 15:21:00 -0400 Received: from foss.arm.com ([217.140.110.172]:36352 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730133AbgGaTU4 (ORCPT ); Fri, 31 Jul 2020 15:20:56 -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 EDC3D106F; Fri, 31 Jul 2020 12:20:55 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9CD4A3F71F; Fri, 31 Jul 2020 12:20:54 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, Quentin Perret , Jonathan Corbet Subject: [PATCH 3/3] sched/doc: Factorize bits between sched-energy.rst & sched-capacity.rst Date: Fri, 31 Jul 2020 20:20:16 +0100 Message-Id: <20200731192016.7484-4-valentin.schneider@arm.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200731192016.7484-1-valentin.schneider@arm.com> References: <20200731192016.7484-1-valentin.schneider@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Documentation/scheduler/sched-capacity.rst ought to be the canonical place to blabber about SD_ASYM_CPUCAPACITY, so remove its explanation from sched-energy.rst and point to sched-capacity.rst instead. Signed-off-by: Valentin Schneider --- Documentation/scheduler/sched-energy.rst | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/Documentation/scheduler/sched-energy.rst b/Documentation/scheduler/sched-energy.rst index 9580c57a52bc..78f850778982 100644 --- a/Documentation/scheduler/sched-energy.rst +++ b/Documentation/scheduler/sched-energy.rst @@ -331,16 +331,8 @@ asymmetric CPU topologies for now. This requirement is checked at run-time by looking for the presence of the SD_ASYM_CPUCAPACITY flag when the scheduling domains are built. -The flag is set/cleared automatically by the scheduler topology code whenever -there are CPUs with different capacities in a root domain. The capacities of -CPUs are provided by arch-specific code through the arch_scale_cpu_capacity() -callback. As an example, arm and arm64 share an implementation of this callback -which uses a combination of CPUFreq data and device-tree bindings to compute the -capacity of CPUs (see drivers/base/arch_topology.c for more details). - -So, in order to use EAS on your platform your architecture must implement the -arch_scale_cpu_capacity() callback, and some of the CPUs must have a lower -capacity than others. +See Documentation/sched/sched-capacity.rst for requirements to be met for this +flag to be set in the sched_domain hierarchy. Please note that EAS is not fundamentally incompatible with SMP, but no significant savings on SMP platforms have been observed yet. This restriction -- 2.27.0