Hi,
We have a number of Intel 82599EB 10-Gigabit dual port NICs running in a number of servers. On a couple of these servers, we are seeing very strange behaviour where when connecting via a Brocade 1G/10G switch from a 1G server we are getting line speed RX (113MB/s) but only a fraction of this TX, for example:
# ./netperf -H XXX.XXX.XXX.XXX -f M
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to XXX.XXX.XXX.XXX () port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. MBytes/sec
2097152 65536 65536 10.14 113.16
# ./netperf -H XXX.XXX.XXX.XXX -f M -t TCP_MAERTS
MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to XXX.XXX.XXX.XXX () port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. MBytes/sec
87380 2097152 2097152 10.00 20.38
We have another server with the same card and that behaves as expected (line speed both TX and RX). As far as I can tell all network configs are the same on both boxes. We've tried different switch, cable, OS and server hardware.
Am I missing something really obvious here?!
Thanks,
Chris