Hi Mike
it seems that running in passive wait is causing some loss, this is due to the
poor buffering power in i40e cards: when there is no packets, the application
calls poll() to wait for new packets until an interrupt is raised, then it 
wakes up
and continue processing traffic. What happens is that the buffer fills up during
this period of time, discarding some packet.
In essence it could be that 1. the poll/wake up period takes too much in passive
wait, or 2. the cpu is in power saving mode slowing down processing (please
check that it is set to “performance” in your Bios) when there is no much to do.
This also depends a lot on the traffic rate, we will run some test to check how
poll behaves at that rate.

Note that this does not happen with -a as the application is not calling poll(),
but it’s just spinning on the cpu.

Alfredo

> On 15 Dec 2017, at 22:00, Lang, Michael <[email protected]> wrote:
> 
> Alfredo,
> 
> Here is what that looks like (much better, I don’t understand why):
> 

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