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 9E488C47247 for ; Fri, 8 May 2020 14:58:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D1852070B for ; Fri, 8 May 2020 14:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728212AbgEHO65 (ORCPT ); Fri, 8 May 2020 10:58:57 -0400 Received: from foss.arm.com ([217.140.110.172]:49730 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726690AbgEHO64 (ORCPT ); Fri, 8 May 2020 10:58:56 -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 2C2C01FB; Fri, 8 May 2020 07:58:56 -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 9AC403F305; Fri, 8 May 2020 07:58:53 -0700 (PDT) References: <20200507180553.9993-1-john.mathew@unikie.com> <20200507180553.9993-3-john.mathew@unikie.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Dietmar Eggemann Cc: John Mathew , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, corbet@lwn.net, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, tsbogend@alpha.franken.de, lukas.bulwahn@gmail.com, x86@kernel.org, linux-mips@vger.kernel.org, tglx@linutronix.de, mostafa.chamanara@basemark.com, rdunlap@infradead.org, Oleg Tsymbal Subject: Re: [RFC PATCH v3 2/3] docs: scheduler: Add scheduler overview documentation In-reply-to: Date: Fri, 08 May 2020 15:58:51 +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 08/05/20 11:58, Dietmar Eggemann wrote: > On 07/05/2020 23:15, Valentin Schneider wrote: >> >> On 07/05/20 19:05, John Mathew wrote: > > [...] > >> It would also be an opportunity to have one place to (at least briefly) >> describe what the different sched classes do wrt capacity asymmetry - CFS >> does one thing, RT now does one thing (see Qais' work), and DL will >> hopefully soon follow (see Dietmar's work). >> >> I'd be happy to contribute (some of) that, if it can be deemed useful (I >> personally think it might). > > I like the idea. > > Essentially all the code which is guarded by the 'if > (static_branch_unlikely(&sched_asym_cpucapacity)' condition or which > sets it during bring-up. > > * 'Cpu capacity < SCHED_LOAD_SCALE for non-big' CPUs setting during > bringup (necessary dt binding, CPUfreq influence) > > * CFS capacity awareness: > > * wakeup - select_idle_capacity() (replaced wake_cap() & slow path to > cover DynamIQ and classical big.LITTLE) > > * load_balance - misfit handling > > * RT & DL capacity awareness > > * ... & the relation to EAS (Documentation/scheduler/sched-energy.rst) > > This is what we referred to (at least internally) as CAS (Capacity-Aware > Scheduling). Yeah, something like that. I'll sharpen my quill and have a go at it, though it won't be for right now with OSPM and the other ongoing stuff.