[ovs-dev] iperf tcp issue on veth using afxdp

[Ilya Maximets]

On 22.11.2019 18:51, William Tu wrote:
> Hi Ilya and Eelco,
> 
> Yiyang reports very poor TCP performance on his setup and I can
> also reproduce it on my machine. Somehow I think this might be a
> kernel issue, but I don't know where to debug this. Need your suggestion
> about how to debug.
> 
> So the setup is like the system-traffic, creating 2 namespaces and
> veth devices and attach to OVS. I do remember to turn off tx offload
> and ping, UDP, nc (tcp-mode) works fine.
> 
> TCP using iperf drops to 0Mbps after 4 seconds.

The key questions are:
* What is your kernel version?
* Does it work in generic mode?
* Does it work if iperf generates UDP traffic?
  ex. iperf3 -c 10.1.1.1 -t 3600 -u -b 10G/64 -l 1460
* It seems like a ring breakage or a umem memory leak.
  So, what are the afxdp related coverage counters?
* Does OVS forward packets, i.e. if there something received/sent?

Best regards, Ilya Maximets.