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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,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 129B7C28CC5 for ; Sun, 9 Jun 2019 01:55:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8F05216C8 for ; Sun, 9 Jun 2019 01:55:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="LiIQZXHv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728139AbfFIBzW (ORCPT ); Sat, 8 Jun 2019 21:55:22 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:38994 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727444AbfFIBzW (ORCPT ); Sat, 8 Jun 2019 21:55:22 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x591sjiX047014; Sun, 9 Jun 2019 01:54:45 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-2018-07-02; bh=VbEHN/1QClutR//aKQqhr92z0vYm5E31Frkb2yISumQ=; b=LiIQZXHvwljGFQm11jDaAbO+wgfCvhBs+aeVLOjvR5X1Fj7QXklHhO+INYPzOZ4FxJ/b D1X8I4frknJvKUg1QyBgijfmanyVRW0QSuuYqkVVzLRVa0nL3VsM5l60yWv5BzTwJrwn NRMv3D4Lm9w/BGP7onv/jjNi0NGBVmJ8hUgsFCr8Ot12xGNYdVtb/c0DX4WSjE5lIC6k vqT1F95s15s8csWlMbHAB5fhzaT1Fd30Qig/TxDhp0NiZxFmD1gkSvKkL6kI8KTw+KA5 Yw/Fkn1tb6mVAMR4JHATx3tsp5kuqfTSC8htN5FLBy84xxa+T8yRAPyhxTxCjbb5yhfV qg== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2130.oracle.com with ESMTP id 2t02hea9wn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 09 Jun 2019 01:54:45 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x591sf7B108928; Sun, 9 Jun 2019 01:54:44 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 2t04bku22s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 09 Jun 2019 01:54:44 +0000 Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x591scaH024571; Sun, 9 Jun 2019 01:54:39 GMT Received: from smazumda-Precision-T1600.us.oracle.com (/10.132.91.175) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 08 Jun 2019 18:54:38 -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, daniel.lezcano@linaro.org, vincent.guittot@linaro.org, viresh.kumar@linaro.org, tim.c.chen@linux.intel.com, mgorman@techsingularity.net Subject: [PATCH v3 1/7] sched: limit cpu search in select_idle_cpu Date: Sat, 8 Jun 2019 18:49:48 -0700 Message-Id: <20190609014954.1033-2-subhra.mazumdar@oracle.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20190609014954.1033-1-subhra.mazumdar@oracle.com> References: <20190609014954.1033-1-subhra.mazumdar@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9282 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=2 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906090012 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9282 signatures=668687 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=999 adultscore=1 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906090013 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Put upper and lower limit on cpu search of select_idle_cpu. The lower limit is amount of cpus in a core while upper limit is twice that. This ensures for any architecture we will usually search beyond a core. The upper limit also helps in keeping the search cost low and constant. Signed-off-by: subhra mazumdar --- kernel/sched/fair.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f35930f..b58f08f 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, nr = INT_MAX; + int cpu, limit, floor, nr = INT_MAX; this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); if (!this_sd) @@ -6206,10 +6206,17 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t if (sched_feat(SIS_PROP)) { u64 span_avg = sd->span_weight * avg_idle; - if (span_avg > 4*avg_cost) + floor = cpumask_weight(topology_sibling_cpumask(target)); + if (floor < 2) + floor = 2; + limit = floor << 1; + if (span_avg > floor*avg_cost) { nr = div_u64(span_avg, avg_cost); - else - nr = 4; + if (nr > limit) + nr = limit; + } else { + nr = floor; + } } time = local_clock(); -- 2.9.3