On Mon, 29 Nov 2021 14:59:53 +0100 Jesper Dangaard Brouer wrote:

Hmm... I don't agree here.  IMHO the BPF-program's *choice* to drop (via 
XDP_DROP) should NOT share the counter with the driver-related drops.

The driver-related drops must be accounted separate.

+1 FWIW. The Tx stat is a little misleading because it differs from the
definition of our other tx stats which mean _successfully_ transmitted
(and are accounted on the completion path in many drivers).

In the past I've used act_*, e.g. act_tx, to indicate the stat counts
returned actions, not whether the packet made it.

I still wonder whether it makes sense to count the stats per-action or
just have one "XDP consumed it" stat and that's it. The semantics of the
action are not of interest to the admin. A firewall can drop or tx
depending if it wants to send an ICMP reject or TCP RST message in
response. I need to know what the application does to understand the
difference, and if I do I can as well look at app stats. But I'm aware
I'm not going to find much support for this position, so just saying...
;)