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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 E40ADC004D2 for ; Tue, 2 Oct 2018 11:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B12FC20666 for ; Tue, 2 Oct 2018 11:54:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B12FC20666 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727584AbeJBShS (ORCPT ); Tue, 2 Oct 2018 14:37:18 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:49368 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727434AbeJBShS (ORCPT ); Tue, 2 Oct 2018 14:37:18 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w92Bru1x031054 for ; Tue, 2 Oct 2018 07:54:22 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2mv7w30nf4-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 02 Oct 2018 07:54:21 -0400 Received: from localhost by e06smtp01.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) Tue, 2 Oct 2018 12:54:16 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w92BsFX162980242 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 2 Oct 2018 11:54:16 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BF660AE056; Tue, 2 Oct 2018 14:53:08 +0100 (BST) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 176BBAE045; Tue, 2 Oct 2018 14:53:07 +0100 (BST) Received: from linux.vnet.ibm.com (unknown [9.102.1.150]) by d06av26.portsmouth.uk.ibm.com (Postfix) with SMTP; Tue, 2 Oct 2018 14:53:06 +0100 (BST) Date: Tue, 2 Oct 2018 17:24:12 +0530 From: Srikar Dronamraju To: Mel Gorman Cc: Peter Zijlstra , Ingo Molnar , Jirka Hladky , Rik van Riel , LKML , Linux-MM Subject: Re: [PATCH 1/2] mm, numa: Remove rate-limiting of automatic numa balancing migration Reply-To: Srikar Dronamraju References: <20181001100525.29789-1-mgorman@techsingularity.net> <20181001100525.29789-2-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20181001100525.29789-2-mgorman@techsingularity.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 18100211-4275-0000-0000-000002C3C107 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18100211-4276-0000-0000-000037CED08F Message-Id: <20181002115412.GA4593@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-10-02_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810020119 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mel Gorman [2018-10-01 11:05:24]: > Rate limiting of page migrations due to automatic NUMA balancing was > introduced to mitigate the worst-case scenario of migrating at high > frequency due to false sharing or slowly ping-ponging between nodes. > Since then, a lot of effort was spent on correctly identifying these > pages and avoiding unnecessary migrations and the safety net may no longer > be required. > > Jirka Hladky reported a regression in 4.17 due to a scheduler patch that > avoids spreading STREAM tasks wide prematurely. However, once the task > was properly placed, it delayed migrating the memory due to rate limiting. > Increasing the limit fixed the problem for him. > > Currently, the limit is hard-coded and does not account for the real > capabilities of the hardware. Even if an estimate was attempted, it would > not properly account for the number of memory controllers and it could > not account for the amount of bandwidth used for normal accesses. Rather > than fudging, this patch simply eliminates the rate limiting. > > However, Jirka reports that a STREAM configuration using multiple > processes achieved similar performance to 4.16. In local tests, this patch > improved performance of STREAM relative to the baseline but it is somewhat > machine-dependent. Most workloads show little or not performance difference > implying that there is not a heavily reliance on the throttling mechanism > and it is safe to remove. > > STREAM on 2-socket machine > 4.19.0-rc5 4.19.0-rc5 > numab-v1r1 noratelimit-v1r1 > MB/sec copy 43298.52 ( 0.00%) 44673.38 ( 3.18%) > MB/sec scale 30115.06 ( 0.00%) 31293.06 ( 3.91%) > MB/sec add 32825.12 ( 0.00%) 34883.62 ( 6.27%) > MB/sec triad 32549.52 ( 0.00%) 34906.60 ( 7.24% > > Signed-off-by: Mel Gorman > --- Reviewed-by: Srikar Dronamraju -- Thanks and Regards Srikar Dronamraju