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Slow UDP outgoing traffic

(Alfven) #1

I’m experiencing an issue in a test scenario with high UDP traffic sent out from containers running on an Atomic Host VM.
The host server has two dedicated 1Gbit NICs: one for ingress traffic and another one for the egress traffic.

When sending small UDP packets (300 bytes) from a container developed by me, I’ve have noticed a reduced throughput and the max used bandwidth is about 159 mbit/sec, while the expected bandwidth is about 600 mbit/sec.

I’ve have repeated the test with iperf docker ( and the result is the same.

Ingress traffic does not have any kind of issue using both our and iperf docker.

On the ingress NIC I had to set the driver to VirtIO, since with the e1000 we had very bad performances.
While on the egress card I have noticed better performances with e1000 than VirtIO but the throughput is still poor and the used bandwidth is still 159 mbit/sec.

Any suggestion on how to increase egress traffic?

(Alfven) #2

I’ve found out the root cause, it’s related to the base image used for the mentioned docker.
For the community, in case someone gets stuck with the same issue it’s suggested to start from “ubuntu” that provides better I/O performances.