Bug#425355: Acknowledgement (dpt_i2o - disk IO causes very high load)

[Peter Hirdina <Peter.Hirdina@gmx.net>]

Some additional information about my system:

* Tyan Tiger MPX (AMD760MPX Chipset)
* 2x Athlon MP 2800+
* 2GB registered ECC RAM
* Adaptec 2400A with 4 disks configured as RAID-5

I know about the PCI performance problems of the 768 southbridge. From
what I've read on the net so far, it seems that only write performance
is really affected, being limited to ~25MB/s. Read Performance seems to
be OK.

If I compare those values with the ones I get from system, then I'm
quite disappointed. I can hardly squeeze 15MB/s out of my RAID (shared
betweend reads and writes). So if I copy a file on the RAID from one
directory to another, this works at a whopping speed of ~7MB/s.

Also if read on the net, that the primary PCI bus on the MPX platform
doesn't have those problems, and a lot of people were seeing drastic
performance improvements when they moved their PCI cards to the 64bit
slots. I tried that as well, but the difference is hardly worth
mentioning (performance improved to around 17MB/s).

So my conclusion is, that there is something else wrong here.

cheers,
    Peter