perfSONAR User Q&A and Other Discussion

[Brian Tierney <>]

interesting.

what type of NIC is in this host?


On Feb 14, 2012, at 11:20 AM, Joseph Bernard wrote:

> One more thing I've noticed.  When I do TCP in PS-PS, the server side CPU
> gets to 80%.  When I do UDP, the CPU only gets to 45%.  On CentOS 5.7, the
> CPU goes to 20% on TCP and 99% on UDP.
> 
> 
> Thanks,
> Joseph
> 
> 
> On 2/14/12 11:30 AM, "Joseph Bernard" 
> <>
>  wrote:
> 
>> I used the -w option and got closer to 700Mb/s. I even put it at 64M to
>> see if it made a difference.  I decided to install CentOS 5.7 i386 and got
>> 950Mb/s on both TCP and UDP, and the limit with the -w option is 256
>> Kbyte.  Now I'm not sure if PS-PS is slower or if CentOS 5.7 is less
>> accurate.
>> 
>> 
>> Thanks,
>> Joseph
>> 
>> 
>> 
>> 
>> On 2/13/12 5:13 PM, "Brian Tierney" 
>> <>
>>  wrote:
>> 
>>> 
>>> 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
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>> 
>