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=-2.2 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 DF482C43603 for ; Thu, 5 Dec 2019 17:14:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B535520801 for ; Thu, 5 Dec 2019 17:14:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730055AbfLEROF (ORCPT ); Thu, 5 Dec 2019 12:14:05 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59918 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726028AbfLEROF (ORCPT ); Thu, 5 Dec 2019 12:14:05 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xB5H7s18093340 for ; Thu, 5 Dec 2019 12:14:04 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2wq1kk5pac-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 05 Dec 2019 12:14:03 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 5 Dec 2019 17:13:54 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xB5HDri218612324 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 5 Dec 2019 17:13:53 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BF1B0A4053; Thu, 5 Dec 2019 17:13:53 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 62F7EA4059; Thu, 5 Dec 2019 17:13:46 +0000 (GMT) Received: from localhost.localdomain (unknown [9.199.45.8]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 5 Dec 2019 17:13:45 +0000 (GMT) Subject: Re: [RFC 0/3] Introduce per-task latency_tolerance for scheduler hints To: Dietmar Eggemann , Valentin Schneider , linux-kernel@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, vincent.guittot@linaro.org, patrick.bellasi@matbug.net, qais.yousef@arm.com, pavel@ucw.cz, dhaval.giani@oracle.com, qperret@qperret.net, David.Laight@ACULAB.COM, morten.rasmussen@arm.com, pjt@google.com, tj@kernel.org, viresh.kumar@linaro.org, rafael.j.wysocki@intel.com, daniel.lezcano@linaro.org References: <20191125094618.30298-1-parth@linux.ibm.com> <450fc7e2-49d5-d809-281f-7d9a99d3e530@arm.com> <838f233e-fa4c-d5a3-9b50-69e2e121edda@arm.com> From: Parth Shah Date: Thu, 5 Dec 2019 22:43:44 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <838f233e-fa4c-d5a3-9b50-69e2e121edda@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19120517-0012-0000-0000-00000371B925 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19120517-0013-0000-0000-000021AD7EBD Message-Id: <5c5b61fa-e8f7-5aa7-0fe0-91cb0d4736fb@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-05_05:2019-12-04,2019-12-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 clxscore=1015 bulkscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 mlxlogscore=913 spamscore=0 impostorscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912050144 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/5/19 7:33 PM, Dietmar Eggemann wrote: > On 05/12/2019 11:49, Valentin Schneider wrote: >> >> On 05/12/2019 09:24, Dietmar Eggemann wrote: >>> On 25/11/2019 10:46, Parth Shah wrote: >>>> This patch series is based on the discussion started as the "Usecases for >>>> the per-task latency-nice attribute"[1] >>>> >>>> This patch series introduces a new per-task attribute latency_tolerance to >>>> provide the scheduler hints about the latency requirements of the task. >>> >>> I forgot but is there a chance to have this as a per-taskgroup attribute >>> as well? >>> >> >> Peter argued we should go for task attributes first, and then >> cgroup/taskgroups later on: >> >> https://lore.kernel.org/lkml/20190905083127.GA2332@hirez.programming.kicks-ass.net/ > > OK, I went through this thread again. So Google or we have to provide > the missing per-taskgroup API via cpu controller's attributes (like for > uclamp) for the EAS usecase. I suppose many others (including myself) will also be interested in having per-taskgroup attribute via CPU controller. > > After reading: > > https://lore.kernel.org/r/20190905114030.GL2349@hirez.programming.kicks-ass.net > > IMHO the following mapping of the existing Android (binary) > latency_sensitive per-taskgroup flag makes sense: > > latency_sensitive=1 -> latency_tolerance*[-20 .. -1] (less tolerant, > more sensitive) > > latency_sensitive=0 -> latency_tolerance[0 .. 19] (more tolerant, less > sensitive) > > Default value is 0 so not latency_sensitive. > > * Since we use [-20 .. 19] as values for latency_tolerance we could name > it latency_nice. It's shorter ... ? I kept choosing appropriate name and possible values for this new attribute in the separate thread. https://lkml.org/lkml/2019/9/30/215 >From which discussion, looking at Patrick's comment https://lkml.org/lkml/2019/9/18/678 I thought of picking latency_tolerance as the appropriate name. Still will be happy to change as per the community needs. Thanks, parth