[tulip] v0.92 and NetPIPE 2.4

[John Connett]

I have been conducting some performance tests on three flavours of
tulip cards (Kingston KNE100TX; KNE110TX; KNE111TX) using NetPIPE 2.4 
(http://www.scl.ameslab.gov/netpipe/).

The tests used two systems connected back-to-back with a crossover
cable.

    receiver: 533MHz Alpha 21164 running Red Hat 6.2
              kernel 2.2.16-3
              KNE100TX (Digital DS21140 Tulip rev 34)

    transmitter: 806MHz Intel PIII running Red Hat 6.2
                 kernel 2.2.16-3smp
                 KNE100TX (Digital DS21140 Tulip rev 34)
                 KNE110TX (Lite-On 82c168 PNIC rev 32)
                 KNE111TX (Lite-On PNIC-II rev 37)

On receiver I ran "mii-diag -A 0x0080 eth2" to restrict it to
advertising 100baseTx-HD and ran the NetPIPE server with "NPtcp -r".

On transmitter I ran:

  NPtcp -t -h receiver -u 1000000 -P -o <output>

Using the default Red Hat 6.2 driver ("tulip.c:91g-ppc 7/16/99 ...")
produced reasonable results for all three cards.

However, using the latest driver ("tulip.c:v0.92 4/17/2000 ...") on
transmitter produced a very marked loss of performance (~66Mbit/s to
~0.6Mbit/s) for block sizes of 4093 bytes and above with the KNE110TX
and KNE111TX.  The KNE100TX appeared to stick trying to process a 4093
byte transfer.

Can anyone shed some light on this behaviour?  Any comments or
suggestions would be gratefully received.  I can supply further
information if that would be helpful.
--
John Connett (jrc@art-render.com)