From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754318Ab3DKJCv (ORCPT ); Thu, 11 Apr 2013 05:02:51 -0400 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:35016 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752743Ab3DKJCt (ORCPT ); Thu, 11 Apr 2013 05:02:49 -0400 Message-ID: <51667C2E.1070605@linux.vnet.ibm.com> Date: Thu, 11 Apr 2013 17:02:38 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Mike Galbraith CC: Peter Zijlstra , Peter Zijlstra , LKML , Ingo Molnar , Alex Shi , Namhyung Kim , Paul Turner , Andrew Morton , "Nikunj A. Dadhania" , Ram Pai Subject: Re: [PATCH] sched: wake-affine throttle References: <5164DCE7.8080906@linux.vnet.ibm.com> <1365583873.30071.31.camel@laptop> <51652F43.7000300@linux.vnet.ibm.com> <516651C8.307@linux.vnet.ibm.com> <1365665447.19620.102.camel@marge.simpson.net> <516673BF.4080404@linux.vnet.ibm.com> <1365669862.19620.129.camel@marge.simpson.net> In-Reply-To: <1365669862.19620.129.camel@marge.simpson.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13041108-9574-0000-0000-0000076B83C0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/11/2013 04:44 PM, Mike Galbraith wrote: > On Thu, 2013-04-11 at 16:26 +0800, Michael Wang wrote: > >> The 1:N is a good reason to explain why the chance that wakee's hot data >> cached on curr_cpu is lower, and since it's just 'lower' not 'extinct', >> after the throttle interval large enough, it will be balanced, this >> could be proved, since during my test, when the interval become too big, >> the improvement start to drop. > > Magnitude of improvement drops just because there's less damage done > methinks. You'll eventually run out of measurable damage :) > > Yes, it's not really extinct, you _can_ reap a gain, it's just not at > all likely to work out. A more symetric load will fare better, but any > 1:N thing just has to spread far and wide to have any chance to perform. Agree. >> Hmm...that's an interesting point, the workload contain different >> 'priority' works, and depend on each other, if mother starving, all the >> kids could do nothing but wait for her, may be that's the reason why the >> benefit is so significant, since in such case, mother's little quicker >> respond will make all the kids happy :) > > Exactly. The entire load is server latency bound. Keep the server on > cpu, the load performs as best it can given unavoidable data miss cost. Nice point :) Regards, Michael Wang > > -Mike >