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Date: Wed, 22 Mar 1995 21:32:15 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199503221132.VAA11806@godzilla.zeta.org.au>
To: freebsd-hackers@freefall.cdrom.com, kuku@gilberto.physik.rwth-aachen.de
Subject: Re: Why IDE is bad
Sender: hackers-owner@FreeBSD.org
Precedence: bulk

>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.

Bruce