[dpdk-users] KNI RX/TX Jitter non symmetrical

[Antoine POLLENUS <a.pollenus@deltacast.tv>]

Hello,

I'm testing the KNI with iperf and I discovered something strange. RX KNI and TX KNI seems to not be symmetrical (in term of latency jitter) and I don't understand why.

I'm using iperf with low packet rate:

This command is launch from a machine that is not running DPDK connected in point to point to a machine using a KNI interface:

sudo iperf -c 10.0.0.2 -u -i 1 -t 3000 -l 54 -b 10368b -f b

and the iperf server is launched on the machine with the KNI interface

sudo iperf -s -u -i 1

And when I look at the jitter. The Jitter is always around 2.5ms

but when I launch

sudo iperf -c 10.0.0.2 -u -i 1 -t 3000 -l 54 -b 10368b -f b

on the machine with the KNI interface and the server

sudo iperf -s -u -i 1

on the non DPDK machine I have Jitter at around 0.002ms

Can someone explain me what is the reason of this huge difference in term of jitter ?

Regards,

Antoine Pollenus