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_PASS 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 268B1C1B0F2 for ; Wed, 20 Jun 2018 08:36:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8318208B0 for ; Wed, 20 Jun 2018 08:36:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8318208B0 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 S1754730AbeFTIge (ORCPT ); Wed, 20 Jun 2018 04:36:34 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:33244 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753906AbeFTIgb (ORCPT ); Wed, 20 Jun 2018 04:36:31 -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 CA93F80D; Wed, 20 Jun 2018 00:58:18 -0700 (PDT) Received: from e108498-lin.cambridge.arm.com (e108498-lin.cambridge.arm.com [10.1.211.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D72F63F246; Wed, 20 Jun 2018 00:58:14 -0700 (PDT) Date: Wed, 20 Jun 2018 08:58:09 +0100 From: Quentin Perret To: Peter Zijlstra Cc: rjw@rjwysocki.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joelaf@google.com, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org Subject: Re: [RFC PATCH v3 05/10] sched/topology: Reference the Energy Model of CPUs when available Message-ID: <20180620075809.GA23168@e108498-lin.cambridge.arm.com> References: <20180521142505.6522-1-quentin.perret@arm.com> <20180521142505.6522-6-quentin.perret@arm.com> <20180619122632.GS2458@hirez.programming.kicks-ass.net> <20180619132449.GA17720@e108498-lin.cambridge.arm.com> <20180619162042.GT2458@hirez.programming.kicks-ass.net> <20180619171316.GB29374@e108498-lin.cambridge.arm.com> <20180619184250.GF2494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180619184250.GF2494@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 19 Jun 2018 at 20:42:50 (+0200), Peter Zijlstra wrote: > On Tue, Jun 19, 2018 at 06:13:17PM +0100, Quentin Perret wrote: > > Would replacing the static_key by a flag attached to the root_domain be > > reasonable ? > > Keep the static key as is, enable if any root domain needs it. OK. So basically the semantics of the static key becomes: it is set if at least one root domain has a non-empty list of freq domains. And a root_domain has a non-empty list of frequency domains if it meets all conditions for EAS (SD_ASYM_CPUCAPACITY flag set, low complexity for the "portion" of the EM covering it, ...) And then, checking the status of the list (empty or not) for a specific root domain can replace my flag I guess. I'll need to check that somewhere around select_task_rq_fair() in addition to the check on the static key to decide if a task can go in find_energy_efficient_cpu(). > > Sorry but I didn't understand that ... > > If you have only a single freq-domain, there is nothing to do, right? Ah, right. Since we already agreed that all CPUs in a freq domain must have the same micro-arch, that's correct. Checking the presence of the SD_ASYM_CPUCAPACITY flag should cover this case I guess. Thanks, Quentin