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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id EA6BEC5CFF1 for ; Tue, 12 Jun 2018 17:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9FB2720660 for ; Tue, 12 Jun 2018 17:49:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="YL9w044v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FB2720660 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.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 S934465AbeFLRtb (ORCPT ); Tue, 12 Jun 2018 13:49:31 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:59902 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934060AbeFLRsk (ORCPT ); Tue, 12 Jun 2018 13:48:40 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5CHjwPc072155; Tue, 12 Jun 2018 17:48:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2017-10-26; bh=wXkNaYS3WkjGPZE38G0sDH96xXhgl8/RE3r4ST5R3gU=; b=YL9w044vMlaoOPQFT+o6GMSjGPEqSRnCXsEtSwoH+Ia6b73Rd027dzQ1W0oimNnNJ0W7 LqjYHtsbrRotS/Q5P4tCaYlT58KvE4imqEBHzUFiywzqzLalRqzwLIa98tnJdA6AEzPf 8lmDk7ZGW8z8EA3lwSCyrADDsBwDhHqplrgiPUmrTa5Fl5M6VN9dAujh4qT/82VlJBVq h/bgzVEdyKf+cb+wjC2bE/K6lK6ZHK4wFq4gTkk+d7hpFayq0h8YuxSW0BEw/Ea1iXmG RHWDCHBytrlHS9ObRevoMh5Xch2Q5Z1ubEM1cK/FlkwjbFDgZURJySdLbKThtxwvylHe sg== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2130.oracle.com with ESMTP id 2jg6b1k4qv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jun 2018 17:48:10 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5CHm7PH027505 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jun 2018 17:48:07 GMT Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5CHm6Y8006223; Tue, 12 Jun 2018 17:48:07 GMT Received: from smazumda-Precision-T1600.us.oracle.com (/10.132.91.87) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 12 Jun 2018 10:48:06 -0700 From: subhra mazumdar To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, steven.sistare@oracle.com, dhaval.giani@oracle.com, rohit.k.jain@oracle.com, daniel.lezcano@linaro.org Subject: [PATCH 3/5] sched: rotate the cpu search window for better spread Date: Tue, 12 Jun 2018 10:50:00 -0700 Message-Id: <20180612175002.31453-4-subhra.mazumdar@oracle.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20180612175002.31453-1-subhra.mazumdar@oracle.com> References: <20180612175002.31453-1-subhra.mazumdar@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8922 signatures=668702 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=658 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806120198 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rotate the cpu search window for better spread of threads. This will ensure an idle cpu will quickly be found if one exists. Signed-off-by: subhra mazumdar --- kernel/sched/fair.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9a6d28d..849c7c8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6372,7 +6372,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t u64 avg_cost, avg_idle; u64 time, cost; s64 delta; - int cpu, limit, floor, nr = INT_MAX; + int cpu, limit, floor, target_tmp, nr = INT_MAX; this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); if (!this_sd) @@ -6403,9 +6403,15 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t } } + if (per_cpu(next_cpu, target) != -1) + target_tmp = per_cpu(next_cpu, target); + else + target_tmp = target; + time = local_clock(); - for_each_cpu_wrap(cpu, sched_domain_span(sd), target) { + for_each_cpu_wrap(cpu, sched_domain_span(sd), target_tmp) { + per_cpu(next_cpu, target) = cpu; if (!--nr) return -1; if (!cpumask_test_cpu(cpu, &p->cpus_allowed)) -- 2.9.3