Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753902AbYJDPF2 (ORCPT ); Sat, 4 Oct 2008 11:05:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753069AbYJDPFL (ORCPT ); Sat, 4 Oct 2008 11:05:11 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:52137 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753029AbYJDPFJ (ORCPT ); Sat, 4 Oct 2008 11:05:09 -0400 From: KOSAKI Motohiro To: Rik van Riel Subject: Re: [PATCH 00/32] Swap over NFS - v19 Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Peter Zijlstra , Linus Torvalds , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no, Daniel Lezcano , Pekka Enberg , Neil Brown , David Miller In-Reply-To: <20081003153810.5dd0a33e@bree.surriel.com> References: <20081002124748.638c95ff.akpm@linux-foundation.org> <20081003153810.5dd0a33e@bree.surriel.com> Message-Id: <20081004232549.CE53.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Date: Sun, 5 Oct 2008 00:05:05 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2791 Lines: 93 Hi > Andrew Morton wrote: > > On Thu, 02 Oct 2008 15:05:04 +0200 Peter Zijlstra wrote: > > > > > Let's get this ball rolling... > > > > I don't think we're really able to get any MM balls rolling until we > > get all the split-LRU stuff landed. Is anyone testing it? Is it good? > > I've done some testing on it on my two test systems and have not > found performance regressions against the mainline VM. > > As for stability, I think we have done enough testing to conclude > that it is stable by now. Also my experience doesn't found any regression. and in my experience, split-lru patch increase performance stability. What is performance stability? example, HPC parallel compution use many process and communication each other. Then, the system performance is decided by most slow process. So, peek and average performance isn't only important, but also worst case performance is important. Especially, split-lru outperform mainline in anon and file mixed workload. example, I ran himeno benchmark. (this is one of most famous hpc benchmark in japan, this benchmark do matrix calculation on large memory (= use anon only)) machine ------------- CPU IA64 x8 MEM 8G benchmark setting ---------------- # of parallel: 4 use mem: 1.7G x4 (used nealy total mem) first: result of when other process stoped (Unit: MFLOPS) each process result 1 2 3 4 worst average --------------------------------------------------------- 2.6.27-rc8: 217 213 217 154 154 200 mmotm 02 Oct: 217 214 217 217 214 216 ok, these are the almost same next: result of when another io process running (Unit: MFLOPS) (*) infinite loop of dd command used each process result 1 2 3 4 worst average --------------------------------------------------------- 2.6.27-rc8: 34 205 69 196 34 126 mmotm 02 Oct: 162 179 146 178 146 166 Wow, worst case is significant difference. (this result is reprodusable) because reclaim processing of mainline VM is too slow. then, the process of calling direct reclaim is decreased performance largely. this characteristics is not useful for hpc, but also useful for desktop. because if X server (or another critical process) call direct reclaim, it can strike end-user-experience easily. yup, I know many people want to other benchmark result too. I'll try to mesure other bench at next week. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/