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=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 37979C5519F for ; Wed, 18 Nov 2020 12:06:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C89C02463B for ; Wed, 18 Nov 2020 12:06:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728095AbgKRMGq (ORCPT ); Wed, 18 Nov 2020 07:06:46 -0500 Received: from foss.arm.com ([217.140.110.172]:53094 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726731AbgKRMGp (ORCPT ); Wed, 18 Nov 2020 07:06:45 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E705011D4; Wed, 18 Nov 2020 04:06:44 -0800 (PST) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0FA0B3F70D; Wed, 18 Nov 2020 04:06:42 -0800 (PST) References: <20201116200428.47359-1-aubrey.li@linux.intel.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Aubrey Li Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, mgorman@techsingularity.net, qais.yousef@arm.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org, Aubrey Li , Mel Gorman , Jiang Biao Subject: Re: [RFC PATCH v4] sched/fair: select idle cpu from idle cpumask for task wakeup In-reply-to: <20201116200428.47359-1-aubrey.li@linux.intel.com> Date: Wed, 18 Nov 2020 12:06:36 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/11/20 20:04, Aubrey Li wrote: > From: Aubrey Li > > Add idle cpumask to track idle cpus in sched domain. When a CPU > enters idle, if the idle driver indicates to stop tick, this CPU > is set in the idle cpumask to be a wakeup target. And if the CPU > is not in idle, the CPU is cleared in idle cpumask during scheduler > tick to ratelimit idle cpumask update. > > When a task wakes up to select an idle cpu, scanning idle cpumask > has low cost than scanning all the cpus in last level cache domain, > especially when the system is heavily loaded. > > Benchmarks were tested on a x86 4 socket system with 24 cores per > socket and 2 hyperthreads per core, total 192 CPUs. Hackbench and > schbench have no notable change, uperf has: > > uperf throughput: netperf workload, tcp_nodelay, r/w size = 90 > > threads baseline-avg %std patch-avg %std > 96 1 0.83 1.23 3.27 > 144 1 1.03 1.67 2.67 > 192 1 0.69 1.81 3.59 > 240 1 2.84 1.51 2.67 > > Cc: Mel Gorman > Cc: Vincent Guittot > Cc: Qais Yousef > Cc: Valentin Schneider > Cc: Jiang Biao > Cc: Tim Chen > Signed-off-by: Aubrey Li That's missing a v3 -> v4 change summary