Date: Wed, 22 Mar 1995 03:39:29 -0800 From: David Greenman <davidg@Root.COM> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-hackers@freefall.cdrom.com, kuku@gilberto.physik.rwth-aachen.de Subject: Re: Why IDE is bad Message-ID: <199503221139.DAA00719@corbin.Root.COM> In-Reply-To: Your message of "Wed, 22 Mar 95 21:32:15 %2B1000." <199503221132.VAA11806@godzilla.zeta.org.au>
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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. Bounce buffers are not used on wd-style drives. -DG
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