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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DFEF1C4361B for ; Fri, 18 Dec 2020 14:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2E7823A84 for ; Fri, 18 Dec 2020 14:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727866AbgLRO00 (ORCPT ); Fri, 18 Dec 2020 09:26:26 -0500 Received: from foss.arm.com ([217.140.110.172]:36412 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727358AbgLRO0Z (ORCPT ); Fri, 18 Dec 2020 09:26:25 -0500 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 071E41FB; Fri, 18 Dec 2020 06:25:40 -0800 (PST) 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 2A6EE3F66B; Fri, 18 Dec 2020 06:25:38 -0800 (PST) References: <20201218103258.GA3040@hirez.programming.kicks-ass.net> <20201218133655.GA10123@e123083-lin> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Morten Rasmussen Cc: Peter Zijlstra , "Rafael J. Wysocki" , Ingo Molnar , Thomas Gleixner , Vincent Guittot , dietmar.eggemann@arm.com, patrick.bellasi@matbug.net, lenb@kernel.org, linux-kernel@vger.kernel.org, ionela.voinescu@arm.com, qperret@google.com, viresh.kumar@linaro.org Subject: Re: [PATCH] sched: Add schedutil overview In-reply-to: <20201218133655.GA10123@e123083-lin> Date: Fri, 18 Dec 2020 14:25:33 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/12/20 13:40, Morten Rasmussen wrote: > On Fri, Dec 18, 2020 at 11:33:09AM +0000, Valentin Schneider wrote: >> (also, does this need a word about runnable rt tasks => goto max?) > > What is actually the intended policy there? I thought it was goto max > unless rt was clamped, but if I read the code correctly in > schedutil_cpu_util() the current policy is only goto max if uclamp isn't > in use at all, including cfs. > Right, so the policy pretty much is: by default, if there are runnable rt tasks, goto max freq. When uclamp isn't used, that's hardcoded. When uclamp is in use, the default RT uclamp.min is 1024, so it "naturally" drives frequency selection to the max when there are runnable RT tasks (rq-aggregated uclamp.min == 1024). That default (uclamp_util_min_rt_default) can be tweaked. > The write-up looks good to me. > > Reviewed-by: Morten Rasmussen > > Morten