[netperf-talk] TCP_MAERTS "len was -1" issue

[Eric Hultin]

We have been running TCP_STREAM tests with no problems with the following 
command line on Linux:

./netperf -H 10.18.212.230 -l 5 -t TCP_STREAM -f k  -- -s 64K -S 64K -m 
64K -M 64K

Normally, we telnet on to the two PCs and perform a simultaneous test by 
running netperf on both units simultaneously. Due to some issues in our 
lab we are starting to use the TCP_MAERTS test to gather performance 
numbers so that we can run both the upstream and downstream tests from a 
single computer. However we are noticing the following problem:

./netperf -H 10.18.212.230 -l 5 -t TCP_MAERTS -f k  -- -s 64K -S 64K -m 
64K -M 64K
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.18.212.230 
(10.18.212.230) port 0 AF_INET
send_tcp_maerts: data recv error: Interrupted system call
len was -1

When we run without the buffer settings it seems to work OK:

./netperf -H 10.18.212.230 -l 5 -t TCP_MAERTS -f k  --
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.18.212.230 
(10.18.212.230) port 0 AF_INET
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^3bits/sec

 87380  16384  16384    7.70      119.11

Also, the TCP_STREAM test seems to work correctly on the other machine 
when we try emulating what the TCP_MAERTS test should be doing. We are 
running this with a Cable Modem which is rate limited to 128K/64K DS/US. 
This behavior was seen on netperf 2.4.0, 2.4.2, and a copy built from the 
latest subversion repository. This is running on  Fedora Core 2 with the 
2.6.10 kernel. Thanks in advance for any advice you can provide.

-EH
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