Questions regarding AF_XDP (ETF, TX queue selection)

["Deric, Nemanja" <nemanja.deric@siemens.com>]

Dear XDP-newbies,

I am Nemanja Deric, and I am working as a Researcher for Industrial 
Networking Department of Siemens AG (Munich, Germany). Recently, 
we have started looking into AF_XDP/XDP and its applicability for some 
of our industrial use cases. Thus, we have a few questions about the 
technology which we hope that this mailing list can help us clarify.

If you believe that these questions are better suited for some other 
mailing list or direct email contact, please let me know so that I can 
contact the correct person/mailing list.

ETF, Timestamping:
In comparison to AF_PACKET sockets AF_XDP sockets do not support 
timestamping (SOL_TXTIME) yet. There seems no way to pass such 
request or meta-information to the kernel / NIC. Is that correct? We 
already heard about "xdp hints" but we have failed to get further 
information like plans / roadmap / implementation state / ideas. 
Any pointers where to look at?

TX queue selection:
AF_XDP sockets are always bound to a specific RX queue. Instead, 
TX queues are "automatically" chosen by the kernel - TX is more or 
less handled by NAPI. Correct? Has someone already thought about 
TX queue selection? Any plans / roadmap / details according 
implementation state available?

In advance, thank you for your help.

Regards,
Nemanja