From owner-freebsd-stable Mon Mar 12 22:28:24 2001 Delivered-To: freebsd-stable@freebsd.org Received: from peak.mountin.net (peak.mountin.net [207.227.119.2]) by hub.freebsd.org (Postfix) with ESMTP id 7F6E437B719; Mon, 12 Mar 2001 22:28:21 -0800 (PST) (envelope-from jeff-ml@mountin.net) Received: (from daemon@localhost) by peak.mountin.net (8.9.1/8.9.1) id AAA17666; Tue, 13 Mar 2001 00:28:20 -0600 (CST) (envelope-from jeff-ml@mountin.net) Received: from dial-69.max1.wa.cyberlynk.net(207.227.118.69) by peak.mountin.net via smap (V1.3) id sma017636; Tue Mar 13 00:27:45 2001 Message-Id: <4.3.2.20010313002151.02d94c70@207.227.119.2> X-Sender: jeff-ml@207.227.119.2 X-Mailer: QUALCOMM Windows Eudora Version 4.3 Date: Tue, 13 Mar 2001 00:24:01 -0600 To: Jean-Marc Zucconi , freebsd-stable@FreeBSD.ORG From: "Jeffrey J. Mountin" Subject: Re: UDMA 33/UDMA 100 perfs In-Reply-To: <200103130329.f2D3TXN73556@freefall.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG At 07:29 PM 3/12/01 -0800, Jean-Marc Zucconi wrote: >Is this the normal behavior expected? > >1) >ata0-master: DMA limited to UDMA33, non-ATA66 compliant cable >ad0: 19092MB [38792/16/63] at ata0-master using UDMA33 ># dd if=/dev/ad0e of=/dev/null bs=1m count=1000 >1048576000 bytes transferred in 49.445390 secs (21206750 bytes/sec) > >2) >ad0: 19092MB [38792/16/63] at ata0-master UDMA100 ># dd if=/dev/ad0e of=/dev/null bs=1m count=1000 >1048576000 bytes transferred in 49.337278 secs (21253220 bytes/sec) > >I get the same performance in both cases. This is with a 4.3-BETA >kernel. I have only one drive on the IDE bus. Just because the speed limit goes up doesn't mean your car will go faster. To wit there are few drives that can exceed what UDMA33 can handle and only then would the higher "speed limit" help. Jeff Mountin - jeff@mountin.net Systems/Network Administrator FreeBSD - the power to serve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message