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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 6B18BC48BD7 for ; Tue, 25 Jun 2019 04:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C2D4208CA for ; Tue, 25 Jun 2019 04:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727055AbfFYEiG (ORCPT ); Tue, 25 Jun 2019 00:38:06 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:29664 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726933AbfFYEhm (ORCPT ); Tue, 25 Jun 2019 00:37:42 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5P4X7cj141938 for ; Tue, 25 Jun 2019 00:37:41 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tbadfcc7b-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 25 Jun 2019 00:37:40 -0400 Received: from localhost by e06smtp01.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) Tue, 25 Jun 2019 05:37:35 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5P4bYjo33751518 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Jun 2019 04:37:34 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CA47511C05B; Tue, 25 Jun 2019 04:37:34 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9969511C050; Tue, 25 Jun 2019 04:37:33 +0000 (GMT) Received: from localhost.in.ibm.com (unknown [9.124.35.87]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 25 Jun 2019 04:37:33 +0000 (GMT) From: Parth Shah To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, dietmar.eggemann@arm.com, patrick.bellasi@arm.com Subject: [RFCv3 4/8] sched/fair: Define core capacity to limit task packing Date: Tue, 25 Jun 2019 10:07:22 +0530 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190625043726.21490-1-parth@linux.ibm.com> References: <20190625043726.21490-1-parth@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19062504-4275-0000-0000-00000345534D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062504-4276-0000-0000-000038558DD5 Message-Id: <20190625043726.21490-5-parth@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-25_03:,, 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=8.0.1-1810050000 definitions=main-1906250036 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org This patch defines a method name arch_scale_core_capacity which should return the capacity of the core. This method will be used in the future patches to determine if the spare capacity is left in the core to pack jitter tasks. For some architectures, core capacity does not increase much with the number of threads( or CPUs) in the core. For such cases, architecture specific calculations needs to be done to find core capacity. This patch provides a default implementation for the scaling core capacity. ToDo: As per Peter's comments, if we are getting rid of SMT capacity then we need to find a workaround for limiting task packing. I'm working around that trying to find a solution for the same but would like to get community response first to have better view. Signed-off-by: Parth Shah --- kernel/sched/fair.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e8c5eb339e35..ff3f88d788d8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5929,6 +5929,25 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t return cpu; } +#ifdef CONFIG_SCHED_SMT + +#ifndef arch_scale_core_capacity +static inline unsigned long arch_scale_core_capacity(int first_thread, + unsigned long smt_cap) +{ + /* Default capacity of core is sum of cap of all the threads */ + unsigned long ret = 0; + int sibling; + + for_each_cpu(sibling, cpu_smt_mask(first_thread)) + ret += cpu_rq(sibling)->cpu_capacity; + + return ret; +} +#endif + +#endif + /* * Try and locate an idle core/thread in the LLC cache domain. */ -- 2.17.1