I did a confusing observation on my Arria 10 development board (and also on my custom board).
I did some Ethernet performance tests with iperf3 and sent data from the Arria 10 Board to a host computer using the TCP protocol.
The transmission to a first Windows computer was fine. When I sent the date to another Windows computer (with another network card), the latency of the network connection increase clearly.
Now, the device has a large latency independent on the computer. A network restart on the Arria 10 device solve the issue, until a large amount of data was transmitted to the second “bad” PC.
When I disable the ‘Interrupt Moderation’ on the “Bad” PC, it works without any issue.
Now the ugly thing is, that a single “bad” computer could influence the whole network settings of the arria 10 device. I’m a bit confused and doesn’t really now, how to debug this issue. Has anyone observed a similar issue? Or any hint?
I used different mainline Linux kernels on the arria 10 device (4.1, 4.14 and 5.4) and the observation was always the same. I think it is some issue in the stmmac driver, but I’m not sure and doesn’t really know how to debug them. I’m grateful for any hint or additional information.
Thanks and cheers