perfSONAR User Q&A and Other Discussion

["Uhl, George D. (GSFC-423.0)[Arctic Slope Technical Services, Inc.]" <>]

Hi,

 

I realize this is one of those rare use cases but I have a situation where I need to run a single-ended nuttcp test and reverse the direction of the test flow.  It works fine when I run nuttcp standalone but when I tried it with pscheduler it fails because pscheduler doesn’t set the “-r” nuttcp receiver flag on the client host receiving the reverse test flow. In order to get nuttcp reverse test flows to work both the “-r” and “-F” CLI options are required.  FWIW, it works fine when transmitting tests.

 

NOTE: The default pscheduler access control (server) port is set to 5001 in /etc/pscheduler/tool/nuttcp.conf. This doesn’t work for standalone nuttcp servers who are listening on TCP/5000 (the default nuttcp access control port).  The solution is to specify 5000 on the “--single-ended-port” option in the pscheduler command.

 

Thanks,

George Uhl

NASA GSFC

 

----- Standalone nuttcp test with reverse test flow

# nuttcp -r -i1 -T 5 -F xxx.xxx.xxx.xxx

    5.0000 MB /   1.00 sec =   41.9394 Mbps     0 retrans

    5.1250 MB /   1.00 sec =   42.9944 Mbps     0 retrans

    5.0625 MB /   1.00 sec =   42.4674 Mbps     0 retrans

    5.1250 MB /   1.00 sec =   42.9916 Mbps     0 retrans

    5.0625 MB /   1.00 sec =   42.4667 Mbps     0 retrans

 

   25.8847 MB /   5.11 sec =   42.4596 Mbps 0 %TX 5 %RX 0 retrans 9.59 msRTT

 

 

----- pscheduler nuttcp with reverse test flow fails:

# pscheduler task --tool nuttcp throughput --dest 198.118.243.23 --single-ended  --single-ended-port=5000 --reverse

 

The nuttcp command that pscheduler generates (from pscheduler.log) leaves out the “-r” receiver option which causes the failure

/usr/bin/nuttcp -p 5101 -P 5000 -T 10 -F xxx.xxx.xxx.xxx

 

 

----- running the same pscheduler nuttcp command as above via the CLI but with the receiver flag  (-r) set is successful:

# /usr/bin/nuttcp -p 5101 -P 5000 -T 10 -r -F xxx.xxx.xxx.xxx

   51.3111 MB /  10.16 sec =   42.3535 Mbps 0 %TX 3 %RX 0 retrans 9.81 msRTT

 

 

----- pscheduler single-ended tests work when run as a nuttcp transmitter:

# pscheduler task --tool nuttcp throughput --dest xxx.xxx.xxx.xxx --single-ended  --single-ended-port=5000

Submitting task...

Task URL:

https://localhost/pscheduler/tasks/08b20c40-8c94-4e18-a0cb-9ca6ccca6e7b

Running with tool 'nuttcp'

Fetching first run...

 

Next scheduled run:

https://localhost/pscheduler/tasks/08b20c40-8c94-4e18-a0cb-9ca6ccca6e7b/runs/a83a8cd3-bf91-4baa-b23d-ef61b9aa2829

Starts 2021-04-22T19:19:06Z (~1 seconds)

Ends   2021-04-22T19:19:22Z (~15 seconds)

Waiting for result...

 

Summary

Interval       Throughput     Retransmits    

0.0 - 10.0     43.29 Mbps     19

 

No further runs scheduled.

 

----- The transmit test nuttcp command generated by pscheduler (without the “-t” transmit option set because that is the default)

/usr/bin/nuttcp -p 5101 -P 5000 -T 10 198.118.243.23