From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Sun, 27 Jul 2008 23:50:31 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m6S6oPlI002554 for ; Sun, 27 Jul 2008 23:50:25 -0700 Received: from smtp1.linux-foundation.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 14FAEEB93A4 for ; Sun, 27 Jul 2008 23:51:36 -0700 (PDT) Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org [140.211.169.13]) by cuda.sgi.com with ESMTP id nWQDdV6eKl5YI93I for ; Sun, 27 Jul 2008 23:51:36 -0700 (PDT) Date: Sun, 27 Jul 2008 23:51:24 -0700 From: Andrew Morton Subject: Re: partially uptodate page reads Message-Id: <20080727235124.5b04fd8b.akpm@linux-foundation.org> In-Reply-To: <6.0.0.20.2.20080728115511.045088a8@172.19.0.2> References: <200807250117.11331.nickpiggin@yahoo.com.au> <20080724175913.GA32117@infradead.org> <20080724120841.81c72be9.akpm@linux-foundation.org> <6.0.0.20.2.20080728115511.045088a8@172.19.0.2> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Hisashi Hifumi Cc: Christoph Hellwig , Nick Piggin , jack@ucw.cz, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com On Mon, 28 Jul 2008 13:34:12 +0900 Hisashi Hifumi wrote: > Hi > > >> > > >> > Are there significant numbers of people using block size < page size in > >> > situations where performance is important and significantly improved by > >> > this patch? Can you give any performance numbers to illustrate perhaps? > >> > >> With XFS lots of people use 4k blocksize filesystems on ia64 systems > >> with 16k pages, so an optimization like this would be useful. > > > >As Nick says, we really should have some measurement results which > >confirm this theory. Maybe we did do some but they didn't find theor > >way into the changelog. > > > >I've put the patch on hold until this confirmation data is available. > > > > I've got some performance number. > I wrote a benchmark program and got result number with this program. > This benchmark do: > 1, mount and open a test file. > 2, create a 512MB file. > 3, close a file and umount. > 4, mount and again open a test file. > 5, pwrite randomly 300000 times on a test file. offset is aligned by IO size(1024bytes). > 6, measure time of preading randomly 100000 times on a test file. > > The result was: > 2.6.26 > 330 sec > > 2.6.26-patched > 226 sec > > Arch:i386 > Filesystem:ext3 > Blocksize:1024 bytes > Memory: 1GB > > On ext3/4, a file is written through buffer/block. So random read/write mixed workloads > or random read after random write workloads are optimized with this patch under > pagesize != blocksize environment. This test result showed this. OK, thanks. Those are pretty nice numbers for what is probably a fairly common workload.