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 E3BA2C47247 for ; Thu, 30 Apr 2020 14:33:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA6EF206D9 for ; Thu, 30 Apr 2020 14:33:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbgD3Odm (ORCPT ); Thu, 30 Apr 2020 10:33:42 -0400 Received: from foss.arm.com ([217.140.110.172]:56156 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726853AbgD3Odk (ORCPT ); Thu, 30 Apr 2020 10:33:40 -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 D8BAD1063; Thu, 30 Apr 2020 07:33:39 -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 DA72A3F68F; Thu, 30 Apr 2020 07:33:37 -0700 (PDT) References: <20200424114058.21199-1-benjamin.gaignard@st.com> <7657495.QyJl4BcWH5@kreacher> <30cdecf9-703a-eb2b-7c2b-f1e21c805add@st.com> <70e743cf-b88e-346a-5114-939b8724c83d@arm.com> <6b5cde14-58b3-045d-9413-223e66b87bf0@st.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Benjamin GAIGNARD Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , "viresh.kumar\@linaro.org" , Hugues FRUCHET , "mchehab\@kernel.org" , "mcoquelin.stm32\@gmail.com" , Alexandre TORGUE , "pavel\@ucw.cz" , "len.brown\@intel.com" , "linux-pm\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , "linux-media\@vger.kernel.org" , "linux-stm32\@st-md-mailman.stormreply.com" , "linux-arm-kernel\@lists.infradead.org" , Patrick Bellasi Subject: Re: [RFC 0/3] Introduce cpufreq minimum load QoS In-reply-to: Date: Thu, 30 Apr 2020 15:33:35 +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 30/04/20 14:46, Benjamin GAIGNARD wrote: >> That's not what I meant. >> >> I suppose that the interrupt processing in question takes place in >> process context and so you may set the lower clamp on the utilization >> of the task carrying that out. > > I have try to add this code when starting streaming (before the first > interrupt) the frames from the sensor: > const struct sched_attr sched_attr = { > .sched_util_min = 10000, /* 100% of usage */ Unless you play with SCHED_CAPACITY_SHIFT, the max should be 1024 - i.e. SCHED_CAPACITY_SCALE. That's a really big boost, but that's for you to benchmark. > .sched_flags = SCHED_FLAG_UTIL_CLAMP_MIN, > }; > > sched_setattr(current, &sched_attr); > > I don't see any benefices maybe there is some configuration flags to set. > > How changing sched_util_min could impact cpufreq ondemand governor ? > Does it change the value returned when the governor check the idle time ? > You'll have to use the schedutil governor for uclamp to have an effect. And arguably that's what you should be using, unless something explicitly prevents you from doing that. >> >> Alternatively, that task may be a deadline one.