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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT 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 BDBA0C3A59B for ; Fri, 30 Aug 2019 17:55:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CA0D20659 for ; Fri, 30 Aug 2019 17:55:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="fYPRu+zT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728230AbfH3Rz5 (ORCPT ); Fri, 30 Aug 2019 13:55:57 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:34208 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727924AbfH3Rzx (ORCPT ); Fri, 30 Aug 2019 13:55:53 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7UHt6tF088742; Fri, 30 Aug 2019 17:55:12 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-2019-08-05; bh=6TBcR3z4xqJM0wmVaFettciFd952rvhR5dlqXaUUv48=; b=fYPRu+zTGJ1MuIYtr3IP9HHd/y+sL77rcRmIEjdZYMC/ykGbXKLTiTwcfl/wOC2prheE B55JjDXKYRtfBKaeMmakP3xNXm1AbLmcDyxvsDx+PIZ6CJpq2O5H2KdHylfTbzHMsVom kiGRCBrrOGx3mAv46rTtuSP3XEgbWDmsZqRgHrEr2w9mLR4baCsSw+UK5r8a05WUXMsl xmPdhUriKDJ2Cg0oPbe755VURCkZSyhj39853j/AtGNSwIj2F8BCizvL5ZtgoH/wsO30 MdZtlsSWVd/MuA9qu+N9NIRP8InO8rDcum0S1kD0sBtRh7rcwFHD8sBa5z3hjsJSJVRs Xw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2uq8fsg22t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 30 Aug 2019 17:55:11 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7UHrdbw017994; Fri, 30 Aug 2019 17:54:39 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2upxabkvum-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 30 Aug 2019 17:54:39 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x7UHscpH014866; Fri, 30 Aug 2019 17:54:38 GMT Received: from smazumda-Precision-T1600.us.oracle.com (/10.132.91.113) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 30 Aug 2019 10:54:38 -0700 From: subhra mazumdar To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, tglx@linutronix.de, steven.sistare@oracle.com, dhaval.giani@oracle.com, daniel.lezcano@linaro.org, vincent.guittot@linaro.org, viresh.kumar@linaro.org, tim.c.chen@linux.intel.com, mgorman@techsingularity.net, parth@linux.ibm.com, patrick.bellasi@arm.com Subject: [RFC PATCH 9/9] sched: rotate the cpu search window for better spread Date: Fri, 30 Aug 2019 10:49:44 -0700 Message-Id: <20190830174944.21741-10-subhra.mazumdar@oracle.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20190830174944.21741-1-subhra.mazumdar@oracle.com> References: <20190830174944.21741-1-subhra.mazumdar@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9365 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=912 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908300174 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9365 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=970 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908300174 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 94dd4a32..7419b47 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6188,7 +6188,7 @@ 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, floor, nr = INT_MAX; + int cpu, floor, target_tmp, nr = INT_MAX; this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); if (!this_sd) @@ -6213,9 +6213,15 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t nr = floor; } + 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