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,URIBL_BLOCKED,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 B4C40C35670 for ; Sun, 23 Feb 2020 06:08:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 864D3206ED for ; Sun, 23 Feb 2020 06:08:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726359AbgBWGIj (ORCPT ); Sun, 23 Feb 2020 01:08:39 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:26753 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725978AbgBWGIj (ORCPT ); Sun, 23 Feb 2020 01:08:39 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 01N64rkU074664 for ; Sun, 23 Feb 2020 01:08:38 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yax36dbeg-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 23 Feb 2020 01:08:37 -0500 Received: from localhost by e06smtp02.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) Sun, 23 Feb 2020 06:08:30 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 01N68TJm40173634 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 23 Feb 2020 06:08:29 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4BE604C052; Sun, 23 Feb 2020 06:08:29 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 760224C044; Sun, 23 Feb 2020 06:08:24 +0000 (GMT) Received: from localhost.localdomain (unknown [9.102.3.81]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Sun, 23 Feb 2020 06:08:24 +0000 (GMT) Subject: Re: [PATCH v4 0/5] remove runnable_load_avg and improve group_classify To: Vincent Guittot , 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 Cc: pauld@redhat.com, valentin.schneider@arm.com, hdanton@sina.com References: <20200221132715.20648-1-vincent.guittot@linaro.org> From: Parth Shah Date: Sun, 23 Feb 2020 11:38:23 +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: <20200221132715.20648-1-vincent.guittot@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 20022306-0008-0000-0000-000003559290 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20022306-0009-0000-0000-00004A76A812 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-22_08:2020-02-21,2020-02-22 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 impostorscore=0 bulkscore=0 spamscore=0 suspectscore=0 mlxlogscore=999 priorityscore=1501 lowpriorityscore=0 clxscore=1015 phishscore=0 malwarescore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002230052 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2/21/20 6:57 PM, Vincent Guittot wrote: > This new version stays quite close to the previous one and should > replace without problems the previous one that part of Mel's patchset: > https://lkml.org/lkml/2020/2/14/156 > > NUMA load balancing is the last remaining piece of code that uses the > runnable_load_avg of PELT to balance tasks between nodes. The normal > load_balance has replaced it by a better description of the current state > of the group of cpus. The same policy can be applied to the numa > balancing. > > Once unused, runnable_load_avg can be replaced by a simpler runnable_avg > signal that tracks the waiting time of tasks on rq. Currently, the state > of a group of CPUs is defined thanks to the number of running task and the > level of utilization of rq. But the utilization can be temporarly low > after the migration of a task whereas the rq is still overloaded with > tasks. In such case where tasks were competing for the rq, the > runnable_avg will stay high after the migration. > > Some hackbench results: > > - small arm64 dual quad cores system > hackbench -l (2560/#grp) -g #grp > > grp tip/sched/core +patchset improvement > 1 1,327(+/-10,06 %) 1,247(+/-5,45 %) 5,97 % > 4 1,250(+/- 2,55 %) 1,207(+/-2,12 %) 3,42 % > 8 1,189(+/- 1,47 %) 1,179(+/-1,93 %) 0,90 % > 16 1,221(+/- 3,25 %) 1,219(+/-2,44 %) 0,16 % > > - large arm64 2 nodes / 224 cores system > hackbench -l (256000/#grp) -g #grp > > grp tip/sched/core +patchset improvement > 1 14,197(+/- 2,73 %) 13,917(+/- 2,19 %) 1,98 % > 4 6,817(+/- 1,27 %) 6,523(+/-11,96 %) 4,31 % > 16 2,930(+/- 1,07 %) 2,911(+/- 1,08 %) 0,66 % > 32 2,735(+/- 1,71 %) 2,725(+/- 1,53 %) 0,37 % > 64 2,702(+/- 0,32 %) 2,717(+/- 1,07 %) -0,53 % > 128 3,533(+/-14,66 %) 3,123(+/-12,47 %) 11,59 % > 256 3,918(+/-19,93 %) 3,390(+/- 5,93 %) 13,47 % [...] I performed similar experiment on IBM POWER9 system with 2 nodes 44 cores system (22 per node) - hackbench -l (256000/#grp) -g #grp +-----+----------------+-------+ | grp | tip/sched/core | v4 | +-----+----------------+-------+ | 1 | 76.97 | 76.31 | | 4 | 56.56 | 56.86 | | 8 | 54.23 | 54.25 | | 16 | 53.94 | 53.24 | | 32 | 54.10 | 54.01 | | 64 | 54.38 | 54.35 | | 128 | 55.11 | 55.08 | | 256 | 55.97 | 56.04 | | 512 | 54.81 | 55.5 | +-----+----------------+-------+ - deviation in the result is very marginal ( < 1%) The results shows no changes with respect to the hackbench. I will do further benchmarking to see if any observable changes occurs. - Parth