Date: Wed, 22 Mar 1995 09:32:30 -0800 (PST) From: Poul-Henning Kamp <phk@ref.tfs.com> To: bde@zeta.org.au (Bruce Evans) Cc: freebsd-hackers@freefall.cdrom.com, kuku@gilberto.physik.rwth-aachen.de Subject: Re: Why IDE is bad Message-ID: <199503221732.JAA05890@ref.tfs.com> In-Reply-To: <199503221132.VAA11806@godzilla.zeta.org.au> from "Bruce Evans" at Mar 22, 95 09:32:15 pm
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> >Regarding the difference in CPU utilization, could it be - I don't > >know the driver internals - that it's the bounce buffer technique > >that costs CPU while the SCSI controller uses bus master transfers all > >the time? Or were you comparing VLB EIDE vs. SCSI ? > > This might explain why my Intr time is so much lower than Poul's. > I have only 16MB, and don't use option BOUNCE_BUFFERS. The bcopy() > for bouncing is done in a call from biodone(). biodone() is called > from the interrupt handler, at least for the wd driver. Excuse moi! Why would we need bounce-buffers for wd.c when the IO is done using "REP INSW" ?? -- Poul-Henning Kamp <phk@login.dknet.dk> -- TRW Financial Systems, Inc. 'All relevant people are pertinent' && 'All rude people are impertinent' => 'no rude people are relevant'
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