21143 specific problems

David Sean Friedman dsf+@andrew.cmu.edu
Tue Sep 28 13:40:22 1999

I've been having some problems with the tulip driver on 21143-based
cards. The problem is that the cards seem unable to sustain more than 1
Mb/s on a 100 Mb link when transmitting tcp traffic.

All other traffic has great performance. UDP traffic is ~90Mb/s in
either direction, and receiving TCP traffic is ~60Mb/s.

However, if I use a 21140-based SMC NIC, the TCP transmit traffic is ~60Mb/s.

The setup I am using is as follows. Two PII's hooked up to an Intel 510T
Switch, one with a tulip NIC, the other with an Intel EtherExpress100. I
use ttcp to measure the performance of the tulip.

The debug output from the tulip driver indicates that both tulip NICs
were operating at full duplex.

Switching to Intel NICs, or older tulips is not an option in the short term.

Is there any way to achieve the same performance on the 21143 tulips?

Thanks in advance for any insight,

David Friedman
Carnegie Mellon University