From owner-freebsd-stable@FreeBSD.ORG Wed Dec 20 13:13:45 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 27A1B16A403 for ; Wed, 20 Dec 2006 13:13:45 +0000 (UTC) (envelope-from ohartman@zedat.fu-berlin.de) Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id 72D3F43C9F for ; Wed, 20 Dec 2006 13:13:44 +0000 (GMT) (envelope-from ohartman@zedat.fu-berlin.de) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost1.zedat.fu-berlin.de (Exim 4.62) with esmtp (envelope-from ) id <1Gx0za-0000io-Jj>; Wed, 20 Dec 2006 13:56:18 +0100 Received: from telesto.geoinf.fu-berlin.de ([130.133.86.198]) by inpost2.zedat.fu-berlin.de (Exim 4.62) with esmtpsa (envelope-from ) id <1Gx0za-0003ym-Ib>; Wed, 20 Dec 2006 13:56:18 +0100 Message-ID: <458932F4.5010107@zedat.fu-berlin.de> Date: Wed, 20 Dec 2006 13:56:20 +0100 From: "O. Hartmann" Organization: Freie =?ISO-8859-1?Q?Universit=E4t_Berlin?= User-Agent: Thunderbird 1.5.0.8 (X11/20061218) MIME-Version: 1.0 To: JoaoBR References: <45888C68.10305@paradise.net.nz> <200612200618.12826.joao@matik.com.br> In-Reply-To: <200612200618.12826.joao@matik.com.br> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: 130.133.86.198 Cc: freebsd-stable@freebsd.org, Mark Kirkwood 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: Wed, 20 Dec 2006 13:13:45 -0000 JoaoBR wrote: > On Tuesday 19 December 2006 22:05, Mark Kirkwood wrote: >> In the process of investigating performance in another area I happened >> to be measuring sequential cached reads (in a fairly basic manner): >> >> $ dd if=/dev/zero of=/tmp/file bs=8k count=100000 # create file >> 819200000 bytes transferred in 4.849394 secs (168928321 bytes/sec) hartmann: dd if=/dev/zero of=/tmp/file bs=8k count=100000 100000+0 records in 100000+0 records out 819200000 bytes transferred in 18.540244 secs (44184964 bytes/sec) hartmann: dd if=/dev/zero of=/tmp/file bs=8k count=100000 100000+0 records in 100000+0 records out 819200000 bytes transferred in 18.047627 secs (45391009 bytes/sec) >> >> $ dd of=/dev/null if=/tmp/file bs=8k # read it >> 819200000 bytes transferred in 2.177922 secs (376138354 bytes/sec) hartmann: dd of=/dev/null if=/tmp/file bs=8k 100000+0 records in 100000+0 records out 819200000 bytes transferred in 1.898039 secs (431603332 bytes/sec) >> $ dd of=/dev/null if=/tmp/file bs=8k # read again >> 819200000 bytes transferred in 2.178407 secs (376054620 bytes/sec) hartmann: dd of=/dev/null if=/tmp/file bs=8k 100000+0 records in 100000+0 records out 819200000 bytes transferred in 1.328635 secs (616572658 bytes/sec) >> 819200000 bytes transferred in 2.178407 secs (376054620 bytes/sec) >> $ dd of=/dev/null if=/tmp/file bs=32k # read it >> 819200000 bytes transferred in 1.801944 secs (454620117 bytes/sec) hartmann: dd of=/dev/null if=/tmp/file bs=32k 25000+0 records in 25000+0 records out 819200000 bytes transferred in 1.037108 secs (789888848 bytes/sec) These are my numbers, but the box is not configured to be benchmarked and is a P4/3.0 GHz, HTT enabled, SMP kernel (most recent RELENG_6) with SCHED_ULE enabled. HD interface is ATA100, slightly aged, I guess ... Regards, Oliver