Re: Best example for showing throughput?

[Damien Millescamps <damien.millescamps-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>]

On 05/24/2013 08:51 PM, Patrick Mahan wrote:
>> > 
>> > Are you sending and receiving on the 2 ports at the same time ?
>> > Forwarding in the 2 directions is equivalent to double the bandwidth.
>> > Maybe that 14.88*2 = 29.76 Mpps is too much for your hardware.
>> > 
> Yes I am running traffic both ways.  Interestingly, the amount of drops seem consistent in both directions.  This makes sense since testpmd is spinning off a thread to read from each input queue.
>
Hi Patrick,

If you are using both ports of the same Niantics at the same time then
you won't be able to reach the line-rate on both port. It is a
limitation of the PLX bridge on the board. The expected performance on
port 1 when port 0 is used at line-rate should be around 75% of the
line-rate from what I know.
Since you are forwarding packets from one port to another, the packet
dropped because of this will impact the performance on both ways since
what is dropped on port 1 won't be forwarded for obvious reasons, and
some of the packets from port 0 will be lost while trying to transmit
them on port 1. Eventually, you will end up with the lower performance
of the two ports which seems to be consistent with the performance you
report.

Hope this helps,
-- 
Damien