Subject: pciide performance on alpha
To: None <>
From: Andreas Johansson <>
List: port-alpha
Date: 08/12/1999 09:09:04

I have another question regarding pciide: Is there anyone that has seen
really good performance with pciide and the alpha?

This is my problem:

I have a 164SX with a cypress ide controller. This controller does support
DMA, but with the pciide driver, it delivers about 3.5MB/s with a disk
that can deliver 16MB/s (measured in a i386 system). About a year ago, I
was running Linux on the same machine and I wrote a driver that could
deliver about the double performance with the same interface.

Not satisfied with this, I got myself a pci card that can do UDMA (a
Promise Ultra33, ~$25) and wrote myself a driver for it. This driver does
only produce 4MB/s no matter what I do, but it does use DMA, about 1% CPU
usage. If I compile the driver in an i386 machine, it works like a charm
and I receive the performance I expect in the UDMA modes.

I've been talking to Manuel Bouyer about this, and he couldn't find any
problem with my driver, he could only refer me to port-alpha. So - is
there anyone that has some idea what might be wrong? I have dmesgs,
configurations, source and more detailed information for anyone that is

Thanks in advance!