Hi guys, I stumbled upon an issue and I really hope someone can provide me with some insights.
TL;DR:
On my NanoPi M4 with Kernel 5.10.43 the upload bandwith is limited to about 70 % of the available bandwidth. With Kernel 4.4 it's ~95 % and with the friendlyarm-image I get the 100 % as reference.
Expected behaviour:
Usage of full available bandwidth
I'm running a core version, no desktop. No configuration has been made on all three images and the tests have been performed with:
iperf3 -p 5200 -N -t 20 -c speedtest.wtnet.de
Result with Kernel 5.10.x (Armbian_21.05.1_Nanopim4_buster_current_5.10.35.img): 8.03 Mbits/sec
Result with Kernel 4.4.x (Armbian_21.05.1_Nanopim4_buster_legacy_4.4.213.img): 11.0 Mbits/sec
Result with Friendlyarm-image (rk3399-sd-friendlycore-lite-focal-4.19-arm64-20210617.img): 11.6 Mbits/sec
LAN works fine, I get around ~960 Mbits/sec. So it must be a software issue and I have no idea why it only affects the WAN-side.
I discovered this issue when doing remote backups with rsync and my router only showed me partial bandwidth usage.
So I also tested with scp and finally iperf, all showing same results. Then I downloaded new images of armbian 5.10.x, 4.4.x + friendlyarm-image and did the testing to make sure no configuration from my side caused it.
I have a bit of a feeling this is intended behaviour not to occupy the whole bandwidth but I couldn't find any documentation whatsoever.
If you need more information let me know, I'm new to armbian so pls don't scalp me.
