Date: Mon, 12 Mar 2001 22:35:34 -0800 From: Kent Stewart <kstewart@urx.com> To: "Jeffrey J. Mountin" <jeff-ml@mountin.net> Cc: Jean-Marc Zucconi <jmz@FreeBSD.ORG>, freebsd-stable@FreeBSD.ORG Subject: Re: UDMA 33/UDMA 100 perfs Message-ID: <3AADBFB6.D0595C28@urx.com> References: <4.3.2.20010313002151.02d94c70@207.227.119.2>
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"Jeffrey J. Mountin" wrote: > > 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 <WDC WD200EB-00BHF0> [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 <WDC WD200EB-00BHF0> [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. Especially since they only do this for 3ms at a time. This is what I read that the length of the time burst was. The only was I could get buildworld times down was to add 3 of the ATA-100's onto individual controllers and enable soft-updates. Kent > > 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 -- Kent Stewart Richland, WA mailto:kbstew99@hotmail.com http://kstewart.urx.com/kstewart/index.html FreeBSD News http://daily.daemonnews.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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