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=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 2F048C48BD3 for ; Wed, 26 Jun 2019 22:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E824121726 for ; Wed, 26 Jun 2019 22:53:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="OSPFdwXk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726633AbfFZWxQ (ORCPT ); Wed, 26 Jun 2019 18:53:16 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:39872 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726289AbfFZWxM (ORCPT ); Wed, 26 Jun 2019 18:53:12 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5QMmbTt100137; Wed, 26 Jun 2019 22:52:28 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=qBZ7pNks6jwo/erAtSEGIYGdwoUp6z0ruzJGXHPePbc=; b=OSPFdwXkb8zzsDaUD7p/4rk/q8wqeFrWJluBr0no/A6YEF8DD+FgvoBt0agQagH0KCNI j3YW+MyVDcuMp8XF7EzVsoWDCJg16CNILBKVBTJ1J5XTj8P6ohgI5uPccWP0XSafPaVg /MELywSlXjEsxjgwk9VS1XzgYqPMSnXRyR9fKNDjHv92F6HK6btE8yflNW9YClSaR+TJ OIYccXufbcU0XbRIJqeUl/49zjxjRwnid/QH463+sJnyKRZuN8VOY3r3bkO0gpX+QkSH xuxyCwUAThkdOUxbv6TdOObPh8Yc9jcVJrqLSnl07JQg75cOPk3y2iNOAy+yeDkdBeFD IQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2t9brtd1aa-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jun 2019 22:52:28 +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 x5QMpwXx075672; Wed, 26 Jun 2019 22:52:28 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2t99f4q9x7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jun 2019 22:52:28 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x5QMqQVF015930; Wed, 26 Jun 2019 22:52:26 GMT Received: from smazumda-Precision-T1600.us.oracle.com (/10.132.91.175) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 26 Jun 2019 15:52:26 -0700 From: subhra mazumdar To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, tglx@linutronix.de, prakash.sangappa@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: [RFC PATCH 3/3] sched: introduce tunables to control soft affinity Date: Wed, 26 Jun 2019 15:47:18 -0700 Message-Id: <20190626224718.21973-4-subhra.mazumdar@oracle.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20190626224718.21973-1-subhra.mazumdar@oracle.com> References: <20190626224718.21973-1-subhra.mazumdar@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9300 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=973 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906260261 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9300 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=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906260262 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For different workloads the optimal "softness" of soft affinity can be different. Introduce tunables sched_allowed and sched_preferred that can be tuned via /proc. This allows to chose at what utilization difference the scheduler will chose cpus_allowed over cpus_preferred in the first level of search. Depending on the extent of data sharing, cache coherency overhead of the system etc. the optimal point may vary. Signed-off-by: subhra mazumdar --- include/linux/sched/sysctl.h | 2 ++ kernel/sched/fair.c | 19 ++++++++++++++++++- kernel/sched/sched.h | 2 ++ kernel/sysctl.c | 14 ++++++++++++++ 4 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 99ce6d7..0e75602 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -41,6 +41,8 @@ extern unsigned int sysctl_numa_balancing_scan_size; #ifdef CONFIG_SCHED_DEBUG extern __read_mostly unsigned int sysctl_sched_migration_cost; extern __read_mostly unsigned int sysctl_sched_nr_migrate; +extern __read_mostly unsigned int sysctl_sched_preferred; +extern __read_mostly unsigned int sysctl_sched_allowed; int sched_proc_update_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 53aa7f2..d222d78 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -85,6 +85,8 @@ unsigned int sysctl_sched_wakeup_granularity = 1000000UL; static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; const_debug unsigned int sysctl_sched_migration_cost = 500000UL; +const_debug unsigned int sysctl_sched_preferred = 1UL; +const_debug unsigned int sysctl_sched_allowed = 100UL; #ifdef CONFIG_SMP /* @@ -6739,7 +6741,22 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f int new_cpu = prev_cpu; int want_affine = 0; int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING); - struct cpumask *cpus = &p->cpus_preferred; + int cpux, cpuy; + struct cpumask *cpus; + + if (!p->affinity_unequal) { + cpus = &p->cpus_allowed; + } else { + cpux = cpumask_any(&p->cpus_preferred); + cpus = this_cpu_cpumask_var_ptr(select_idle_mask); + cpumask_andnot(cpus, &p->cpus_allowed, &p->cpus_preferred); + cpuy = cpumask_any(cpus); + if (sysctl_sched_preferred * cpu_rq(cpux)->cfs.avg.util_avg > + sysctl_sched_allowed * cpu_rq(cpuy)->cfs.avg.util_avg) + cpus = &p->cpus_allowed; + else + cpus = &p->cpus_preferred; + } if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index b52ed1a..f856bdb 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1863,6 +1863,8 @@ extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags); extern const_debug unsigned int sysctl_sched_nr_migrate; extern const_debug unsigned int sysctl_sched_migration_cost; +extern const_debug unsigned int sysctl_sched_preferred; +extern const_debug unsigned int sysctl_sched_allowed; #ifdef CONFIG_SCHED_HRTICK diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 7d1008b..bdffb48 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -383,6 +383,20 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "sched_preferred", + .data = &sysctl_sched_preferred, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "sched_allowed", + .data = &sysctl_sched_allowed, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #ifdef CONFIG_SCHEDSTATS { .procname = "sched_schedstats", -- 2.9.3