ng_one2many - very slow

Marko Zec zec at icir.org
Fri Sep 17 04:05:01 PDT 2004


On Friday 17 September 2004 12:17, donatas wrote:
> Hello,
>
> we need a 400Mbit link between two intel machines (Xeon 2.4, Raid,
> 512DDr, 2 ports-em(1000Mbit),2 ports-fxp(100Mbit))
>
> ....
>
> truth, we've tested direct link between em adapters in gigabit mode
> and using TCP packets 850Mbit throughput was achieved. And Nearly
> 1Gbit with UDP packets.
>
> as you see one2many test results aren't even close to 400Mbit
> Is it possible that em and fxp cannot work together or something.
> what can you suggest to solve this small problem?


Perhaps TCP packets are arriving out of order for some reason (interrupt 
coalescing etc.) which can be _bad_ for TCP throughput.  What kind of 
CPU load are you observing on those machines, when testing a single 
Gbit link versus a 4*100M bundle?

Marko


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