perfSONAR User Q&A and Other Discussion

[Brian Tierney <>]

Did you use the -w option with UDP?

TCP autotunes, UDP does not, and to go fast UDP needs more buffer space than 
the default. 

Try adding "-w 4M" to both sender and receiver.

On Feb 13, 2012, at 1:35 PM, Joseph Bernard wrote:

> I loaded 3.2.1.1 on 2 workstations and got 950Mb/s on TCP and 600Mb/s on
> UDP tests.  They both have 1Gb/s cards.  I thought maybe the network cards
> weren't up to snuff, so I got 2 HP servers, loaded them up, and did the
> same tests.  I got the same results.  The workstations/servers are
> connected via crossover.  I even tried a brand new cable to be sure it
> wasn't bad materials.
> 
> When I used my iMac and Macbook Pro from 2009 running Snow Leopard, I was
> able to get 800Mb/s running iperf.  Is there something I am missing?
> 
> 
> Thanks,
> Joseph Bernard
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