Date: Mon, 8 May 1995 15:36:55 -0700 (PDT) From: Tom Samplonius <tom@haven.uniserve.com> To: "Justin T. Gibbs" <gibbs@estienne.CS.Berkeley.EDU> Cc: hackers@FreeBSD.org Subject: Re: Is a 486 fast enough for SCSI? Message-ID: <Pine.BSF.3.91.950508153553.717D-100000@haven.uniserve.com> In-Reply-To: <199505082151.OAA02666@estienne.cs.berkeley.edu>
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On Mon, 8 May 1995, Justin T. Gibbs wrote: > > I've got a AMD486DX4100 with an Adaptec 2940 and two SCSI drives. When > >I run iozone on one drive I get about 1.9MB/s, but when I run a iozone on > >each drive I get about .9 MB/s (roughly half). Since the SCSI bus runs > >at 10MB/s per second, the limiting factor appears to be the CPU? I > >thought PCI devices required very little CPU time? > > > >Tom > > Do you have disconnection disabled on your devices? I don't see anywhere > neer this kind of performance drop off on my 2742 with two drives (One drive > is 5MB/s the other is 2MB/s). Yes, disconnection is enabled. Tom
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