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 D49ACC433EF for ; Mon, 21 Mar 2022 17:24:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351823AbiCURZi (ORCPT ); Mon, 21 Mar 2022 13:25:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345862AbiCURZh (ORCPT ); Mon, 21 Mar 2022 13:25:37 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95962183805 for ; Mon, 21 Mar 2022 10:24:11 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id mr5-20020a17090b238500b001c67366ae93so12424723pjb.4 for ; Mon, 21 Mar 2022 10:24:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JfYPzIW2uZzSE1OyzcQN2ZgSvbN8ua2owpED41aqf8k=; b=cP0Vw/KU+TayukEqk47ZzWLTyhs9Sb6Nnk/xv2Zusp8ePPannwFsRf9qWpavIy/vUH Mthdsilm9/Z2GQOgg2rTFIOzE4gxIiPZDI9q5H0Pq6p7LqWHqxuVfbwYUQoBIhv8Ykdh 5WLOVxxiHFQrby2H+xNZot7gpXtkaxWzJMEJsl8BlBQ+Qm0Ixfwn5vIaQGSRVJDo80sE 8+2hEYP/f54KuFdlkzTHxh23nVk2qMy+K8PSfoloz5wfQ1cS9ZGOKp6afCoVdDeB9rg8 Hz0dVPJunBc92nnCR48bm7Vr+buIVzXEA7aq9fl8K5f+p/nLJmSgLsrDJYOlP6E1tf1F KxAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=JfYPzIW2uZzSE1OyzcQN2ZgSvbN8ua2owpED41aqf8k=; b=QnHAptyifEkf8R29jQ4hzbVGrBGYmvuh+XCd+39YG3xVQgRDX8oe8OHXn/i6qmzUVF 46mqPab+cV5NkRfssbhhyVS+VlIpo8Th8shi9SAt6tKEzL5ofO3bSJPU1kE6r2av/W2E FC3t4AlTjwCXRf9webGZJ88jNQ/8YfsZ6gncgVcgVMcOSuLhh2Zsvv22rKh/kL8W6hWy 6XJMwPbPK0hRD/0NNFo7hS5iWKAQHJBkgGgjhdiAels4pAHqLz2XSQh1Ppqg0SOIMEE3 qHOMkPV0H35HMBNFG1/Sf22CzxSWkFAPGyANE8VF+bsiU3KiWEW97kj3EXHgK2qXh3az NidA== X-Gm-Message-State: AOAM532VrZ/iWyNj8TI0j8H1kTLm50PAByuLyRCCkSfHgWV90lWM2wHT 9DbFbFu2zaWm/4N6/mtZAkQ= X-Google-Smtp-Source: ABdhPJxktdHHIsTKejTvZ1f+liEbHlXdjGAcmQRLIAdUUovCXnZu4jp649ZCQ4dW1JCBky15mgB7fg== X-Received: by 2002:a17:903:246:b0:153:857c:a1f6 with SMTP id j6-20020a170903024600b00153857ca1f6mr13788157plh.153.1647883450916; Mon, 21 Mar 2022 10:24:10 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-e24f-43ff-fee6-449f.res6.spectrum.com. [2603:800c:1a02:1bae:e24f:43ff:fee6:449f]) by smtp.gmail.com with ESMTPSA id y14-20020a62f24e000000b004f7d604f5ddsm19745878pfl.181.2022.03.21.10.24.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Mar 2022 10:24:09 -0700 (PDT) Sender: Tejun Heo Date: Mon, 21 Mar 2022 07:24:07 -1000 From: Tejun Heo To: Vincent Guittot Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org, parth@linux.ibm.com, 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, dhaval.giani@oracle.com, qperret@google.com, tim.c.chen@linux.intel.com Subject: Re: [RFC 6/6] sched/fair: Add sched group latency support Message-ID: References: <20220311161406.23497-1-vincent.guittot@linaro.org> <20220311161406.23497-7-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220311161406.23497-7-vincent.guittot@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Mar 11, 2022 at 05:14:06PM +0100, Vincent Guittot wrote: > Tasks can set its latency priority which is then used to decide to preempt > the current running entity of the cfs but sched group entities still have > the default latency priority. > > Add a latency field in task group to set the latency priority of the group > which will be used against other entity in the parent cfs. One thing that bothers me about this interface is that the configuration values aren't well defined. We have the same problems with the nice levels but at least have them map to well defined weight values, which likely won't change in any foreseeable future. The fact that we have the not-too-well-defined nice levels as an interface shouldn't be a reason we add another one. Provided that this is something scheduler folks want, it'd be really great if the interface can be better thought through. What are the numbers actually encoding? Thanks. -- tejun