Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758087AbcDLVpR (ORCPT ); Tue, 12 Apr 2016 17:45:17 -0400 Received: from mail-wm0-f52.google.com ([74.125.82.52]:33450 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757409AbcDLVpG (ORCPT ); Tue, 12 Apr 2016 17:45:06 -0400 Date: Tue, 12 Apr 2016 22:45:02 +0100 From: Matt Fleming To: Chris Mason , Mike Galbraith , Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] select_idle_sibling experiments Message-ID: <20160412214502.GI2829@codeblueprint.co.uk> References: <20160405180822.tjtyyc3qh4leflfj@floor.thefacebook.com> <1459927644.5612.41.camel@suse.de> <20160409173034.GA85074@clm-mbp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160409173034.GA85074@clm-mbp.thefacebook.com> User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 566 Lines: 15 On Sat, 09 Apr, at 01:30:34PM, Chris Mason wrote: > > [ nohz throttling patch ] > > I tested the nohz throttle two different ways, first with schbench's > pipe simulation, it's easily 8% faster with messages bouncing between > cpus. > > In production it's hard to pick a single number because the benchmarks > produce latency curves as the workload scales up in RPS. The benefits > range from 2-9% depending on the metric. It's a nice win, and I'd love to > see it go in. Do we have any idea what the tradeoff is against power consumption for throttling nohz?