Subject: Re: poor network performance on de0's on 21164's.
To: Paul H. Anderson <pha@pdq.com>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: port-alpha
Date: 07/10/1999 21:27:35
On Sat, Jul 10, 1999 at 06:34:02PM -0400, Paul H. Anderson wrote:
> 
> (Mike - mts@off.to and I work together, so I'm speaking up for a
> second...)
> 
> In our setup, no apparent combination of switch, hub, direct wire, full,
> half duplex, Tulip or Intel card appears to work properly with our 164LX
> boxes.
> 
> It seems that lots of people report partial or complete success with other
> boxes, but after a tremendous amount of time trying many, many different
> combinations (all with 164LX 533MHz alphas), we are simply unable to get
> good symmetric performance, or even adequate performance.

Are you aware that the chipset used on the 164LX boards has at least
one bug which can substantially impact PCI DMA performance?  There's a
workaround, but it's not clear that it restores performance, just correct
operation.

This is one good reason to buy the older PC164 boards and _not_ the SX
or LX boards.  IIRC Jason Thorpe looked into this at some point in the
past and determined that the SX boards had had a hardware workaround
applied by DEC but that it wasn't clear that the LX boards had...