Problems with large packets on DC21143

[Donald Becker]

On Thu, 28 Oct 1999, Andrew Brydon wrote:

> We have recently purchased some Compaq DS10 workstations, which are
> alpha ev6 machines with two builtin tulip 21143 cards. They are running
> RH6.0.
> 
> We noticed that the network performance was terrible, and a quick look
> with netpipe shows that the bandwidth climbs steadily to about 60Mbps
> for 4000 byte packet, but then drops to about 1Mbps for anything larger
> than that. The logs dont seem to show anything particularily useful,
> even with debugging turned on for the tulip module.

Verify the duplex with 'tulip-diag'.
  http://cesdis.gsfc.nasa.gov/linux/diag/index.html

Verify that the 'ttcp -n 10000' performance is over 11MB/sec.

Check for errors in /proc/net/dev

Donald Becker
Scyld Computing Corporation, and
USRA-CESDIS,   becker@cesdis.gsfc.nasa.gov