Intel X520-DA2 performance issues with default NIC ring buffer/descriptors setting

[interduo]

Today I did some new hardware tested with LibreQoS (HP G9, 2x E5-2690 v4, Intel X520-DA2).
I was stuck at ~4-5Gbit/s and on network switch on both ports connected to server with LibreQoS the counter "Rx pause" was significantly ticking. The issue is repetable - it's

Changing buffer rings (from default 512) to maximum supported by card (4096) removes issue.

Also it was visible on our monitoring:

See this big drop on errors/discards graph.

Maybe lqosd shoud also set those parameters to maximum supported by card? (I also see this as another option in http://libreqos:9123/config --> tuning)

It will allow to process more packets at the same time if I proper understand this setting.

TL/TR:

ethtool -G ens16np0 rx 4096 tx 4096
ethtool -A ens16np0 rx off tx off
ethtool -G ens17np0 rx 4096 tx 4096
ethtool -A ens17np0 rx off tx off

[interduo]

@thebracket will You add ringbuffer settings to LQOS config/GUI?