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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7DB62C4360C for ; Fri, 27 Sep 2019 13:53:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 55DCE217D7 for ; Fri, 27 Sep 2019 13:53:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727657AbfI0NxI (ORCPT ); Fri, 27 Sep 2019 09:53:08 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:60707 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726163AbfI0NxI (ORCPT ); Fri, 27 Sep 2019 09:53:08 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id DB93D80551; Fri, 27 Sep 2019 15:52:51 +0200 (CEST) Date: Fri, 27 Sep 2019 15:53:00 +0200 From: Pavel Machek To: Parth Shah Cc: Valentin Schneider , Patrick Bellasi , linux-kernel@vger.kernel.org, Peter Zijlstra , subhra mazumdar , tim.c.chen@linux.intel.com, mingo@redhat.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, pjt@google.com, vincent.guittot@linaro.org, quentin.perret@arm.com, dhaval.giani@oracle.com, daniel.lezcano@linaro.org, tj@kernel.org, rafael.j.wysocki@intel.com, qais.yousef@arm.com, Patrick Bellasi Subject: Re: Usecases for the per-task latency-nice attribute Message-ID: <20190927135259.GB3557@bug> References: <3e5c3f36-b806-5bcc-e666-14dc759a2d7b@linux.ibm.com> <87woe51ydd.fsf@arm.com> <77457d5b-185e-1548-4a5c-9b911b036cec@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > I don't want to start a bikeshedding session here, but I agree with Parth > > on the interpretation of the values. > > > > I've always read niceness values as > > -20 (least nice to the system / other processes) > > +19 (most nice to the system / other processes) > > > > So following this trend I'd see for latency-nice: > > > So jotting down separately, in case if we think to have "latency-nice" > terminology, then we might need to select one of the 2 interpretation: > > 1). > > -20 (least nice to latency, i.e. sacrifice latency for throughput) > > +19 (most nice to latency, i.e. sacrifice throughput for latency) > > > > 2). > -20 (least nice to other task in terms of sacrificing latency, i.e. > latency-sensitive) > +19 (most nice to other tasks in terms of sacrificing latency, i.e. > latency-forgoing) For the record, interpretation 2 makes sense to me. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html