From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 9A28D6B004D for ; Mon, 10 Aug 2009 02:23:53 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n7A6Nv45029834 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 10 Aug 2009 15:23:58 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 00F8945DE54 for ; Mon, 10 Aug 2009 15:23:57 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id AC2EE45DE4F for ; Mon, 10 Aug 2009 15:23:56 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 838751DB803B for ; Mon, 10 Aug 2009 15:23:56 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 39CAD1DB8041 for ; Mon, 10 Aug 2009 15:23:56 +0900 (JST) Date: Mon, 10 Aug 2009 15:22:05 +0900 From: KAMEZAWA Hiroyuki Subject: Re: Help Resource Counters Scale Better (v3) Message-Id: <20090810152205.d37d8e2f.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090810144559.ac5a3499.kamezawa.hiroyu@jp.fujitsu.com> References: <20090807221238.GJ9686@balbir.in.ibm.com> <39eafe409b85053081e9c6826005bb06.squirrel@webmail-b.css.fujitsu.com> <20090808060531.GL9686@balbir.in.ibm.com> <99f2a13990d68c34c76c33581949aefd.squirrel@webmail-b.css.fujitsu.com> <20090809121530.GA5833@balbir.in.ibm.com> <20090810093229.10db7185.kamezawa.hiroyu@jp.fujitsu.com> <20090810053025.GC5257@balbir.in.ibm.com> <20090810144559.ac5a3499.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: balbir@linux.vnet.ibm.com, Andrew Morton , andi.kleen@intel.com, Prarit Bhargava , KOSAKI Motohiro , "lizf@cn.fujitsu.com" , "menage@google.com" , Pavel Emelianov , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: On Mon, 10 Aug 2009 14:45:59 +0900 KAMEZAWA Hiroyuki wrote: > > Do you agree? > > Ok. Config is enough at this stage. > > The last advice for merge is, it's better to show the numbers or > ask someone who have many cpus to measure benefits. Then, Andrew can > know how this is benefical. > (My box has 8 cpus. But maybe your IBM collaegue has some bigger one) > > In my experience (in my own old trial), > - lock contention itself is low. not high. > - but cacheline-miss, pingpong is very very frequent. > > Then, this patch has some benefit logically but, in general, > File-I/O, swapin-swapout, page-allocation/initalize etc..dominates > the performance of usual apps. You'll have to be careful to select apps > to measure the benfits of this patch by application performance. > (And this is why I don't feel so much emergency as you do) > Why I say "I want to see the numbers" again and again is that this is performance improvement with _bad side effect_. If this is an emergent trouble, and need fast-track, which requires us "fix small problems later", plz say so. I have no objection to this approach itself because I can't think of something better, now. percpu-counter's error tolerance is a generic problem and we'll have to visit this anyway. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org