Date: Mon, 1 Apr 1996 17:45:05 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: davidg@Root.COM Cc: dutchman@spase.nl, freebsd-hackers@freebsd.org Subject: Re: HDD cpu usage (IDE vs. SCSI). Message-ID: <199604011545.RAA23295@labinfo.iet.unipi.it> In-Reply-To: <199604011030.CAA08362@Root.COM> from "David Greenman" at Apr 1, 96 02:29:59 am
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> >How come the seagate uses twice as much cpu as the quantum? > > Because a Pentium-90 is much faster than a 486-100 for certain things and > most of the %CPU is for total I/O overhead, not just the overhead in the > device driver. Hmmm... if I get it right this means that under certain circumstances (1 disk, onboard IDE controller, medium-fast CPU) using SCSI instead of IDE gives you only a very little saving (which BTW is what I am convinced of, but this has not been the dominating opinion on this list). Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================
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