From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754039AbZESHKT (ORCPT ); Tue, 19 May 2009 03:10:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753556AbZESHKI (ORCPT ); Tue, 19 May 2009 03:10:08 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:46162 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753432AbZESHKH (ORCPT ); Tue, 19 May 2009 03:10:07 -0400 From: KOSAKI Motohiro To: "Zhang, Yanmin" Subject: Re: [PATCH 4/4] zone_reclaim_mode is always 0 by default Cc: kosaki.motohiro@jp.fujitsu.com, "Wu, Fengguang" , LKML , linux-mm , Andrew Morton , Rik van Riel , Christoph Lameter In-Reply-To: <4D05DB80B95B23498C72C700BD6C2E0B2EF6E313@pdsmsx502.ccr.corp.intel.com> References: <20090519125744.4EC3.A69D9226@jp.fujitsu.com> <4D05DB80B95B23498C72C700BD6C2E0B2EF6E313@pdsmsx502.ccr.corp.intel.com> Message-Id: <20090519141050.4ED5.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 19 May 2009 16:09:58 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi > >>> >>Now, it was breaked. What should we do? > >>> >>Yanmin, We know 99% linux people use intel cpu and you are one of > >>> >>most hard repeated testing > >>> [YM] It's very easy to reproduce them on my machines. :) Sometimes, because > >>the > >>> issues only exist on machines with lots of cpu while other community > >>developers > >>> have no such environments. > >>> > >>> > >>> guy in lkml and you have much test. > >>> >>May I ask your tested machine and benchmark? > >>> [YM] Usually I started lots of benchmark testing against the latest kernel, > >>but > >>> as for this issue, it's reported by a customer firstly. The customer runs > >>apache > >>> on Nehalem machines to access lots of files. So the issue is an example of > >>file > >>> server. > >> > >>hmmm. > >>I'm surprised this report. I didn't know this problem. oh.. > [YM] Did you run file server workload on such NUMA machine with > zone_reclaim_mode=1? If all nodes have the same memory, the behavior is > obvious. I missed your point. I agree file server case is obvious. but I don't think anybody oppose this. > >>Actually, I don't think apache is only file server. > >>apache is one of killer application in linux. it run on very widely > >>organization. > [YM] I know that. Apache could support document, ecommerce, and lots of other > usage models. What I mean is one of customers hit it with their > workload. hmhm, ok. > >>you think large machine don't run apache? I don't think so. > >> > >> > >> > >>> BTW, I found many test cases of fio have big drop after I upgraded BIOS of > >>one > >>> Nehalem machine. By checking vmstat data, I found almost a half memory is > >>always free. It's also related to zone_reclaim_mode because new BIOS changes > >>the node > >>> distance to a large value. I use numactl --interleave=all to walkaround the > >>problem temporarily. > >>> > >>> I have no HPC environment. > >> > >>Yeah, that's ok. I and cristoph have. My worries is my unknown workload become > >>regression. > >>so, May I assume you run your benchmark both zonre reclaim 0 and 1 and you > >>haven't seen regression by non-zone reclaim mode? > [YM] what is non-zone reclaim mode? When zone_reclaim_mode=0? > I didn't do that intentionally. Currently I just make sure FIO has a big drop > when zone_reclaim_mode=1. I might test it with other benchmarks on 2 Nehalem machines. May I ask what is FIO? File IO? > >>if so, it encourage very much to me. > >> > >>if zone reclaim mode disabling don't have regression, I'll pushing to > >>remove default zone reclaim mode completely again. > [YM] I run lots of benchmarks, but it doesn't mean I run all benchmarks, especially > no HPC. Of cource. nobody can run all benchmark in the world :) > >>> >>if zone_reclaim=0 tendency workload is much than zone_reclaim=1 tendency > >>> >>workload, > >>> >> we can drop our afraid and we would prioritize your opinion, of cource. > >>> So it seems only file servers have the issue currently. >