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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 90D70C43140 for ; Wed, 20 Jun 2018 17:04:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E20E20836 for ; Wed, 20 Jun 2018 17:04:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E20E20836 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 S933170AbeFTREI (ORCPT ); Wed, 20 Jun 2018 13:04:08 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41382 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933134AbeFTREF (ORCPT ); Wed, 20 Jun 2018 13:04:05 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5KGww5G035106 for ; Wed, 20 Jun 2018 13:04:04 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jqswv310t-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 20 Jun 2018 13:04:04 -0400 Received: from localhost by e06smtp04.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) Wed, 20 Jun 2018 18:03:58 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5KH3vkJ28115134 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 20 Jun 2018 17:03:57 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0FDBFA404D; Wed, 20 Jun 2018 17:54:38 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9AA5EA4040; Wed, 20 Jun 2018 17:54:36 +0100 (BST) Received: from srikart450.in.ibm.com (unknown [9.124.219.212]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 20 Jun 2018 17:54:36 +0100 (BST) From: Srikar Dronamraju To: Ingo Molnar , Peter Zijlstra Cc: LKML , Mel Gorman , Rik van Riel , Srikar Dronamraju , Thomas Gleixner Subject: [PATCH v2 16/19] sched/numa: Detect if node actively handling migration Date: Wed, 20 Jun 2018 22:32:57 +0530 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1529514181-9842-1-git-send-email-srikar@linux.vnet.ibm.com> References: <1529514181-9842-1-git-send-email-srikar@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18062017-0016-0000-0000-000001DE2FCA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18062017-0017-0000-0000-00003232458D Message-Id: <1529514181-9842-17-git-send-email-srikar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-20_08:,, 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=8.0.1-1805220000 definitions=main-1806200187 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a node is the destination for a task migration under numa balancing, then any parallel movements to the node will be restricted. In such a scenario, detect at the earliest and avoid evaluation for a task movement. While here, avoid task migration if the numa imbalance is very minimal. Especially consider two tasks A and B racing with each other to find the best cpu to swap. If task A already has found one task/cpu pair to swap and trying to find a better cpu. Task B is yet to find a better cpu/task to swap. Task A can race with task B and deprive it from getting a task/cpu to swap. Running SPECjbb2005 on a 4 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 16 25960 26015.6 0.214 1 73550 73484 -0.08 Running SPECjbb2005 on a 16 node machine and comparing bops/JVM JVMS LAST_PATCH WITH_PATCH %CHANGE 8 120071 120453 0.31 1 176249 181140 2.77 Testcase Time: Min Max Avg StdDev numa01.sh Real: 493.19 672.88 597.51 59.38 numa01.sh Sys: 150.09 245.48 207.76 34.26 numa01.sh User: 41928.51 53779.17 48747.06 3901.39 numa02.sh Real: 60.63 62.87 61.22 0.83 numa02.sh Sys: 16.64 27.97 20.25 4.06 numa02.sh User: 5222.92 5309.60 5254.03 29.98 numa03.sh Real: 821.52 902.15 863.60 32.41 numa03.sh Sys: 112.04 130.66 118.35 7.08 numa03.sh User: 62245.16 69165.14 66443.04 2450.32 numa04.sh Real: 414.53 519.57 476.25 37.00 numa04.sh Sys: 181.84 335.67 280.41 54.07 numa04.sh User: 33924.50 39115.39 37343.78 1934.26 numa05.sh Real: 408.30 441.45 417.90 12.05 numa05.sh Sys: 233.41 381.60 295.58 57.37 numa05.sh User: 33301.31 35972.50 34335.19 938.94 Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 428.48 837.17 700.45 162.77 -14.6% numa01.sh Sys: 78.64 247.70 164.45 58.32 26.33% numa01.sh User: 37487.25 63728.06 54399.27 10088.13 -10.3% numa02.sh Real: 60.07 62.65 61.41 0.85 -0.30% numa02.sh Sys: 15.83 29.36 21.04 4.48 -3.75% numa02.sh User: 5194.27 5280.60 5236.55 28.01 0.333% numa03.sh Real: 814.33 881.93 849.69 27.06 1.637% numa03.sh Sys: 111.45 134.02 125.28 7.69 -5.53% numa03.sh User: 63007.36 68013.46 65590.46 2023.37 1.299% numa04.sh Real: 412.19 438.75 424.43 9.28 12.20% numa04.sh Sys: 232.97 315.77 268.98 26.98 4.249% numa04.sh User: 33997.30 35292.88 34711.66 415.78 7.582% numa05.sh Real: 394.88 449.45 424.30 22.53 -1.50% numa05.sh Sys: 262.03 390.10 314.53 51.01 -6.02% numa05.sh User: 33389.03 35684.40 34561.34 942.34 -0.65% Signed-off-by: Srikar Dronamraju --- Changelog v1->v2: - Handle trivial changes due to variable name change. - Also reevaluate node active migration for every cpu. - Now detect active migration in task_numa_find_cpu as suggested by Rik Van Riel. kernel/sched/fair.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9db09a6..c07ac30 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1535,6 +1535,13 @@ static bool load_too_imbalanced(long src_load, long dst_load, } /* + * Maximum numa importance can be 1998 (2*999); + * SMALLIMP @ 30 would be close to 1998/64. + * Used to deter task migration. + */ +#define SMALLIMP 30 + +/* * This checks if the overall compute and NUMA accesses of the system would * be improved if the source tasks was migrated to the target dst_cpu taking * into account that it might be best if task running on the dst_cpu should @@ -1567,7 +1574,7 @@ static void task_numa_compare(struct task_numa_env *env, goto unlock; if (!cur) { - if (maymove || imp > env->best_imp) + if (maymove && moveimp >= env->best_imp) goto assign; else goto unlock; @@ -1610,16 +1617,22 @@ static void task_numa_compare(struct task_numa_env *env, task_weight(cur, env->dst_nid, dist); } - if (imp <= env->best_imp) - goto unlock; - if (maymove && moveimp > imp && moveimp > env->best_imp) { - imp = moveimp - 1; + imp = moveimp; cur = NULL; goto assign; } /* + * If the numa importance is less than SMALLIMP, + * task migration might only result in ping pong + * of tasks and also hurt performance due to cache + * misses. + */ + if (imp < SMALLIMP) + goto unlock; + + /* * In the overloaded case, try and keep the load balanced. */ load = task_h_load(env->p) - task_h_load(cur); @@ -1656,6 +1669,7 @@ static void task_numa_compare(struct task_numa_env *env, static void task_numa_find_cpu(struct task_numa_env *env, long taskimp, long groupimp) { + pg_data_t *pgdat = NODE_DATA(cpu_to_node(env->dst_cpu)); long src_load, dst_load, load; bool maymove = false; int cpu; @@ -1671,12 +1685,14 @@ static void task_numa_find_cpu(struct task_numa_env *env, maymove = !load_too_imbalanced(src_load, dst_load, env); for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) { + bool move = maymove && !READ_ONCE(pgdat->active_node_migrate); + /* Skip this CPU if the source task cannot migrate */ if (!cpumask_test_cpu(cpu, &env->p->cpus_allowed)) continue; env->dst_cpu = cpu; - task_numa_compare(env, taskimp, groupimp, maymove); + task_numa_compare(env, taskimp, groupimp, move); } } -- 1.8.3.1