em0 performance subpar

[Adam Stylinski]

On Thu, Apr 28, 2011 at 11:21:32AM -0400, Mike Tancsa wrote:
> On 4/28/2011 11:01 AM, Adam Stylinski wrote:
> > 
> > ./netblast 192.168.0.121 5001 32768 30
> > 
> > start:             1304002549.184689025
> > finish:            1304002579.187555311
> > send calls:        2163162
> > send errors:       2095950
> > approx send rate:  2240
> > approx error rate: 0
> > 
> > ? This output is a bit cryptic but from what I think I understand from the source code it's the number of successful sends of the payload size in 30 seconds.  
> > 
> > So to do the math: 
> > (32768*2210)/(1024*1024)
> > 69.06250000000000000000MB/sec?  This is still only saturating about half the link speed.
> 
> Just to be clear, you have something listening on the other side on port
> 5001 right ?  ie on 192.168.0.121, you did a ./netreceive 5001... And
> the payload is.... 32768 ?!? Try something that does not need
> fragmentation and is within your max MTU.  e.g. 500 byte frames should
> saturate a gigabit link.
> 
> Watch it in real time with something like ifstat
> 
> ./netblast 192.168.0.121 5001 500 5
> 
> 	---Mike
> 
> 
> 
> 
> -- 
> -------------------
> Mike Tancsa, tel +1 519 651 3400
> Sentex Communications, mike at sentex.net
> Providing Internet services since 1994 www.sentex.net
> Cambridge, Ontario Canada   http://www.tancsa.com/

Listening with iperf on the other end.  The receiving end is a Linux machine, but the code looks to be mainly portable socket code so let me compile netreceive on the linux box and give you the results.
-- 
Adam Stylinski
PGP Key: http://pohl.ececs.uc.edu/~adam/publickey.pub
Blog: http://technicallyliving.blogspot.com
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