Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753543AbdCOM2A (ORCPT ); Wed, 15 Mar 2017 08:28:00 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45968 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751037AbdCOM0v (ORCPT ); Wed, 15 Mar 2017 08:26:51 -0400 Date: Wed, 15 Mar 2017 13:26:47 +0100 From: Peter Zijlstra To: Jarmo Tiitto Cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4.9] sched/fair: Overload-On-Wakeup fix. Message-ID: <20170315122647.GQ3093@worktop> References: <1489527246.3961.3@smtp.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1489527246.3961.3@smtp.gmail.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 975 Lines: 28 On Tue, Mar 14, 2017 at 11:34:06PM +0200, Jarmo Tiitto wrote: > Try improve multi-core scaling. > The changes are experimental - the fix works > but possible regressions are unknown. > > Please read the orginal author's paper to understand > the overall problem this patch tries to solve. > > See the orignal patches at: > https://github.com/jplozi/wastedcores/tree/master/patches > > And the related paper at: > http://www.i3s.unice.fr/~jplozi/wastedcores/ > > v1: the patch was re-written for v4.9 to remove goto statement. > > v2: improved version from the wastedcores initial code. try take into > account the cpu wake-up latency and choose most recent idle cpu > instead. > > I have tested the code and it really does improve > multi-core performance on my machine. v4.9 is not the right kernel to send patches against (hint: v4.10 is not either). Also your Changelog is inadequate; it should be self contained, explain the problem and describe the solution.