From owner-freebsd-stable@FreeBSD.ORG Thu Dec 21 15:10:30 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 2740216A412 for ; Thu, 21 Dec 2006 15:10:30 +0000 (UTC) (envelope-from markir@paradise.net.nz) Received: from smtp4.clear.net.nz (smtp4.clear.net.nz [203.97.37.64]) by mx1.freebsd.org (Postfix) with ESMTP id DD25D13C457 for ; Thu, 21 Dec 2006 15:10:29 +0000 (UTC) (envelope-from markir@paradise.net.nz) Received: from [192.168.1.11] (121-72-71-65.dsl.telstraclear.net [121.72.71.65]) by smtp4.clear.net.nz (CLEAR Net Mail) with ESMTP id <0JAL006GTQ7R1F20@smtp4.clear.net.nz> for freebsd-stable@freebsd.org; Thu, 21 Dec 2006 15:14:15 +1300 (NZDT) Date: Thu, 21 Dec 2006 15:14:04 +1300 From: Mark Kirkwood In-reply-to: <4589A921.90002@paradise.net.nz> To: freebsd-stable@freebsd.org Message-id: <4589EDEC.2040504@paradise.net.nz> MIME-version: 1.0 Content-type: multipart/mixed; boundary=------------060008050409040508000700 References: <45888C68.10305@paradise.net.nz> <200612200816.51043.joao@matik.com.br> <4589128F.9030404@paradise.net.nz> <200612201536.25497.pieter@degoeje.nl> <4589A921.90002@paradise.net.nz> User-Agent: Thunderbird 1.5.0.8 (X11/20061129) X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Pieter de Goeje Subject: Re: Cached file read performance with 6.2-PRERELEASE X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Dec 2006 15:10:30 -0000 This is a multi-part message in MIME format. --------------060008050409040508000700 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mark Kirkwood wrote: > Pieter de Goeje wrote: >> It would be more interesting to see how random access to a (cached) >> file performs in Linux vs FreeBSD, which seems a more logical pattern >> for a database. >> > > Agreed, and good point, I'll knock up a simple program to do random > and/or sequential access of a file and see what we get! > Here's a (very) simple program that does block reads sequentially or randomly. It probably needs a little polishing, but seems to work ok for the size of files we are interested in: i.e < a few GB (see attached): Results: ======== Compiled with CFLAGS=-O2 -march=i686 Gentoo - 2.6.18-gentoo-r3: ----------------------- $ ./readtest /data0/dump/file 8192 0 random reads: 100000 elapsed: 1.2646 io rate 647805551 bytes/s $ ./readtest /data0/dump/file 8192 1 sequential reads: 100000 elapsed: 1.1267 io rate 727075854 bytes/s FreeBSD - 6.2-PRERELEASE #7: Mon Nov 27 19:32:33 NZDT 2006 : ------------------------------------------------------------ ./readtest /data0/dump/file 8192 0 random reads: 100000 elapsed: 4.3669 io rate 187594060 bytes/s $ ./readtest /data0/dump/file 8192 1 sequential reads: 100000 elapsed: 1.9679 io rate 416283642 bytes/s So looks like we get faster overall results than dd (I guess not needing to send output anywhere helps)...also we seem to be slower in the random case too :-(. I ran these programs several times, typical results shown. Cheers Mark --------------060008050409040508000700--