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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3E4B0C43331 for ; Thu, 5 Sep 2019 20:45:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59B642067B for ; Thu, 5 Sep 2019 20:45:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Pn3UjrWJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404033AbfIEUpe (ORCPT ); Thu, 5 Sep 2019 16:45:34 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:37826 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731142AbfIEUpe (ORCPT ); Thu, 5 Sep 2019 16:45:34 -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 x85KhxwM001368; Thu, 5 Sep 2019 20:44:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2019-08-05; bh=aqDnQxZxonMvjcV/XCftl9y61xAtbi3wkQPOl+rmUng=; b=Pn3UjrWJWLwxEHkpvou1UJExMc0Liv/nmZSrk7VX++NAw1ezKbm9WaQf4lURWXxrI1/a Vkw/DVE95sl5Rjy6DwZh/dXUEqp/O8E77IEdgPeQ0AY7CGOTNkOrEZtO8t0cYoaD6flW l1VWePBA1+IPut4Ds8jbbfmNW9ZzTnf9H4EnXfzjaLMsgN3BjKwJy2NpkWUrO7cQKjOB Eu2dAeOXqRApuMG7SVYk3L509nzC4N027wGWsIy4NZfcaWQnwiWk/l7Esak/m7DEsisk IMh/TW6L/ZwV2WJr/VxWgO8X1UDNDFeaGebBsQo6k5NqjkUHA+C9Ol5yTIpa5NLunS+T BA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2uu9g9026y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 05 Sep 2019 20:44:54 +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 x85KhQo5157189; Thu, 5 Sep 2019 20:44:53 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2utpmbtvfy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 05 Sep 2019 20:44:53 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x85Kinhv005857; Thu, 5 Sep 2019 20:44:49 GMT Received: from [10.132.91.113] (/10.132.91.113) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 05 Sep 2019 13:44:49 -0700 Subject: Re: [RFC PATCH 7/9] sched: search SMT before LLC domain To: Peter Zijlstra Cc: linux-kernel@vger.kernel.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 References: <20190830174944.21741-1-subhra.mazumdar@oracle.com> <20190830174944.21741-8-subhra.mazumdar@oracle.com> <20190905093127.GI2349@hirez.programming.kicks-ass.net> From: Subhra Mazumdar Message-ID: Date: Thu, 5 Sep 2019 13:40:47 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190905093127.GI2349@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9371 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909050193 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9371 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default 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=8.0.1-1906280000 definitions=main-1909050193 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/5/19 2:31 AM, Peter Zijlstra wrote: > On Fri, Aug 30, 2019 at 10:49:42AM -0700, subhra mazumdar wrote: >> Search SMT siblings before all CPUs in LLC domain for idle CPU. This helps >> in L1 cache locality. >> --- >> kernel/sched/fair.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 8856503..94dd4a32 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -6274,11 +6274,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) >> return i; >> } >> >> - i = select_idle_cpu(p, sd, target); >> + i = select_idle_smt(p, target); >> if ((unsigned)i < nr_cpumask_bits) >> return i; >> >> - i = select_idle_smt(p, target); >> + i = select_idle_cpu(p, sd, target); >> if ((unsigned)i < nr_cpumask_bits) >> return i; >> > But it is absolutely conceptually wrong. An idle core is a much better > target than an idle sibling. This is select_idle_smt not select_idle_core.