From owner-freebsd-current@FreeBSD.ORG Mon Oct 18 18:10:05 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CCA9516A550 for ; Mon, 18 Oct 2004 18:10:05 +0000 (GMT) Received: from spider.deepcore.dk (cpe.atm2-0-53484.0x50a6c9a6.abnxx9.customer.tele.dk [80.166.201.166]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0ECB443D5A for ; Mon, 18 Oct 2004 18:10:05 +0000 (GMT) (envelope-from sos@DeepCore.dk) Received: from [194.192.25.143] (laptop.deepcore.dk [194.192.25.143]) by spider.deepcore.dk (8.12.11/8.12.10) with ESMTP id i9II9x5o023995; Mon, 18 Oct 2004 20:10:02 +0200 (CEST) (envelope-from sos@DeepCore.dk) Message-ID: <417406E3.9010706@DeepCore.dk> Date: Mon, 18 Oct 2004 20:09:39 +0200 From: =?ISO-8859-1?Q?S=F8ren_Schmidt?= User-Agent: Mozilla Thunderbird 0.7.2 (X11/20040802) X-Accept-Language: en-us, en MIME-Version: 1.0 To: fandino@ng.fadesa.es References: <20041015190638.C5A0E5D04@ptavv.es.net> <41715E7F.7060509@ng.fadesa.es> <20041018100045.f8koww0skcco0woo@www.sweetdreamsracing.biz> <4173D66F.6010200@DeepCore.dk> <4173F2E9.7010407@ng.fadesa.es> In-Reply-To: <4173F2E9.7010407@ng.fadesa.es> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-mail-scanned: by DeepCore Virus & Spam killer v1.4 cc: freebsd-current@freebsd.org Subject: Re: FreeBSD 5.3b7and poor ata performance X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Oct 2004 18:10:05 -0000 fandino wrote: > Hello S=F8ren, >=20 > I was running FreeBSD-4.x for two years with this problem, waiting > for FreeBSD-5 because ATAng looks very promising. >=20 > Unfortunately the performance problem persist :-( and I'd like to > call the attention about performance over raw devices, whilst it's > a very scientific test it's very curious: >=20 > # dd if=3D/dev/ad4 of=3D/dev/null bs=3D1024k count=3D1024 > 1024+0 records in > 1024+0 records out > 1073741824 bytes transferred in 31.090536 secs (34535970 bytes/sec) >=20 > over 34000 K/sec, using raw devices (for sequential access obviously) > not softupdates, filesystems or caches are involved, and with all this > FreeBSD performace is very deficient. Tests with OpenBSD and Linux > using raw devices shows a throughput of approx 60000 K/sec. > The question here is why using low-level access to disks is so bad? I need more info on your system, ie config file dmesg etc. From what you've posted so far I've setup a system with a semilar disk=20 etc, and I get this: dd if=3D/dev/ad10 of=3D/dev/null bs=3D1024k count=3D1024 1024+0 records in 1024+0 records out 1073741824 bytes transferred in 18.488903 secs (58074934 bytes/sec) On a WDC 70G raptor you will see: # dd if=3D/dev/ad4 of=3D/dev/null bs=3D1024k count=3D1024 1024+0 records in 1024+0 records out 1073741824 bytes transferred in 14.956484 secs (71791059 bytes/sec) So there is nothing in FreeBSD-5.3 thats hindering performance in the=20 ATA subsystem as far as I can measure. > Perphas I'm missing something but this seems very weird to me. Most likely, as the result I get are close to what the disks can deliver.= > I'd like to know wich is you opinion about this. If you run a stock generic kernel with the debug (WITNESS etc) taken out = you should see the same raw performance as I do. Now, raw performance is one thing, filesystem I/O something entirely=20 different and not within my area of expertise. I do know that much=20 though, that its very difficult to measure in a way that makes=20 comparison between the different systems possible or even fair. --=20 -S=F8ren