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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 21007ECDFBB for ; Fri, 20 Jul 2018 13:54:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 329CA206B7 for ; Fri, 20 Jul 2018 13:54:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 329CA206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731919AbeGTOmj (ORCPT ); Fri, 20 Jul 2018 10:42:39 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:36686 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727693AbeGTOmj (ORCPT ); Fri, 20 Jul 2018 10:42:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 50D4F80D; Fri, 20 Jul 2018 06:54:14 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CB9BE3F73C; Fri, 20 Jul 2018 06:54:12 -0700 (PDT) Date: Fri, 20 Jul 2018 14:54:10 +0100 From: Morten Rasmussen To: Quentin Perret Cc: peterz@infradead.org, mingo@redhat.com, valentin.schneider@arm.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, gaku.inami.xh@renesas.com, linux-kernel@vger.kernel.org Subject: Re: [PATCHv4 11/12] sched/core: Disable SD_ASYM_CPUCAPACITY for root_domains without asymmetry Message-ID: <20180720135410.GD19287@e105550-lin.cambridge.arm.com> References: <1530699470-29808-1-git-send-email-morten.rasmussen@arm.com> <1530699470-29808-12-git-send-email-morten.rasmussen@arm.com> <20180705133142.GD32579@e108498-lin.cambridge.arm.com> <20180705141349.GD8596@e105550-lin.cambridge.arm.com> <20180705150311.GE32579@e108498-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180705150311.GE32579@e108498-lin.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 05, 2018 at 04:03:11PM +0100, Quentin Perret wrote: > On Thursday 05 Jul 2018 at 15:13:49 (+0100), Morten Rasmussen wrote: > > 3. Detecting the flag in generic kernel/sched/* code means that all > > architectures will pay the for the overhead when building/rebuilding the > > sched_domain hierarchy, and all architectures that sets the cpu > > capacities to asymmetric will set the flag whether they like it or not. > > I'm not sure if this is a problem. > > That is true as well ... > > > > > In the end it is really about how much of this we want in generic code > > and how much we hide in arch/, and if we dare to touch the sched_domain > > build code ;-) > > Right so you can argue that the arch code is here to give you a > system-level information, and that if the scheduler wants to virtually > split that system, then it's its job to make sure that happens properly. > That is exactly what your patch does (IIUC), and I now think that this > is a very sensible middle-ground option. But this is debatable so I'm > interested to see what others think :-) I went ahead an hacked up some patches that sets the flag automatically as part of the sched_domain build process. I posted them so people can have a look: 1532093554-30504-1-git-send-email-morten.rasmussen@arm.com With those patches this patch has to be reverted/dropped. Morten