Roland> I might get a chance to do it tonight... I'll post if I do.

I'm giving it a shot but I just can't reproduce this well on my
systems.  I do see a pretty big regression between 2.6.12-rc4 and
2.6.14-rc2, but 2.6.12-rc5 looks OK on my systems.

I reflashed to FW 4.7.0 (mem-ful) and built netperf 2.4.1.

With 2.6.12-rc4 I've seen runs as slow as:

    TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.145.2 (192.168.145.2) port 0 AF_INET
    Recv   Send    Send                          Utilization       Service Demand
    Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
    Size   Size    Size     Time     Throughput  local    remote   local   remote
    bytes  bytes   bytes    secs.    MBytes  /s  % S      % U      us/KB   us/KB
    
     87380  16384  16384    10.00       553.71   37.46    -1.00    2.642   -1.000

and with 2.6.12-rc5 I've seen runs as fast as:

    TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.145.2 (192.168.145.2) port 0 AF_INET
    Recv   Send    Send                          Utilization       Service Demand
    Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
    Size   Size    Size     Time     Throughput  local    remote   local   remote
    bytes  bytes   bytes    secs.    MBytes  /s  % S      % U      us/KB   us/KB
    
     87380  16384  16384    10.00       581.82   39.58    -1.00    2.657   -1.000

so not much difference there.  With 2.6.14-rc2, the best of 10 runs was:

    TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.145.2 (192.168.145.2) port 0 AF_INET
    Recv   Send    Send                          Utilization       Service Demand
    Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
    Size   Size    Size     Time     Throughput  local    remote   local   remote
    bytes  bytes   bytes    secs.    MBytes  /s  % S      % U      us/KB   us/KB
    
     87380  16384  16384    10.01       497.00   39.71    -1.00    3.121   -1.000

so we've definitely lost something there.

Time to do some more bisecting...

 - R.