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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BC9FC433EF for ; Mon, 28 Mar 2022 09:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239797AbiC1J0F (ORCPT ); Mon, 28 Mar 2022 05:26:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239804AbiC1J0A (ORCPT ); Mon, 28 Mar 2022 05:26:00 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 68D6E1659C for ; Mon, 28 Mar 2022 02:24:20 -0700 (PDT) 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 221D7150C; Mon, 28 Mar 2022 02:24:20 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 372273F66F; Mon, 28 Mar 2022 02:24:17 -0700 (PDT) Message-ID: <7a7e1e21-df3d-4623-d9cd-51f5272919d5@arm.com> Date: Mon, 28 Mar 2022 11:24:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 0/6] Add latency_nice priority Content-Language: en-US To: Vincent Guittot , mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org, parth@linux.ibm.com Cc: qais.yousef@arm.com, chris.hyser@oracle.com, pkondeti@codeaurora.org, valentin.schneider@arm.com, patrick.bellasi@matbug.net, David.Laight@aculab.com, pjt@google.com, pavel@ucw.cz, tj@kernel.org, dhaval.giani@oracle.com, qperret@google.com, tim.c.chen@linux.intel.com References: <20220311161406.23497-1-vincent.guittot@linaro.org> From: Dietmar Eggemann In-Reply-To: <20220311161406.23497-1-vincent.guittot@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/03/2022 17:14, Vincent Guittot wrote: > This patchset restarts the work about adding a latency nice priority to > describe the latency tolerance of cfs tasks. > > The patches [1-4] have been done by Parth: > https://lore.kernel.org/lkml/20200228090755.22829-1-parth@linux.ibm.com/ > > I have just rebased and moved the set of latency priority outside the > priority update. I have removed the reviewed tag because the patches > are 2 years old. > > The patches [5-6] use latency nice priority to decide if a cfs task can > preempt the current running task. Patch 5 gives some tests results with > cyclictests and hackbench to highlight the benefit of latency nice > priority for short interactive task or long intensive tasks. The Android specific `latency_nice` (in Android `latency_sensitive` [latency_nice < 0]) use case `Skip energy aware task placement` favors an idle CPU over the EAS search path for a `latency_sensitive` task. https://lkml.kernel.org/r/2aa4b838-c298-ec7d-08f3-caa50cc87dc2@arm.com This is Android proprietary code similar to what we have in find_idlest_group_cpu() in mainline. We talked to the Android folks last week and IMHO they are not convinced that they can switch this to the proposed `latency_nice->tweak preemption` use case.