From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752400AbeA3NTC (ORCPT ); Tue, 30 Jan 2018 08:19:02 -0500 Received: from outbound-smtp27.blacknight.com ([81.17.249.195]:56607 "EHLO outbound-smtp27.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752143AbeA3NTB (ORCPT ); Tue, 30 Jan 2018 08:19:01 -0500 Date: Tue, 30 Jan 2018 13:18:59 +0000 From: Mel Gorman To: Peter Zijlstra Cc: Mike Galbraith , Matt Fleming , LKML Subject: Re: [PATCH 4/4] sched/fair: Use a recently used CPU as an idle candidate and the basis for SIS Message-ID: <20180130131859.rvhobozd5lvt6hs5@techsingularity.net> References: <20180130104555.4125-1-mgorman@techsingularity.net> <20180130104555.4125-5-mgorman@techsingularity.net> <20180130115349.GB2269@hirez.programming.kicks-ass.net> <20180130130606.GH2295@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20180130130606.GH2295@hirez.programming.kicks-ass.net> User-Agent: NeoMutt/20170912 (1.9.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 30, 2018 at 02:06:06PM +0100, Peter Zijlstra wrote: > On Tue, Jan 30, 2018 at 12:53:49PM +0100, Peter Zijlstra wrote: > > On Tue, Jan 30, 2018 at 10:45:55AM +0000, Mel Gorman wrote: > > > The results can be less dramatic on NUMA where automatic balancing interferes > > > with the test. It's also known that network benchmarks running on localhost > > > also benefit quite a bit from this patch (roughly 10% on netperf RR for UDP > > > and TCP depending on the machine). Hackbench also seens small improvements > > > (6-11% depending on machine and thread count). The facebook schbench was also > > > tested but in most cases showed little or no different to wakeup latencies. > > > > What cpufreq setting were you using for these tests? > > I cannot measure any hackbench variation one way or the other with these > patches using 'performance' mode. So I'll assume you've been running > things with HWP or something. Correct, I am not using the performance governor as it's not the default and not necessarily desirable as a default. HWP in some cases is enabled but even machines using the intel_pstate driver on machines without HWP benefit. -- Mel Gorman SUSE Labs