On 2/2/20 12:31 PM, Jakub Kicinski wrote:

I think our perspectives will be difficult to reconcile.

My reading is that you look at this from slow software device
perspective. Of which there are few (and already loaded with hacks).
And you want the control plane to be simple rather than performance.

I look at this from HW driver perspective of which there are many.
Saying that it's fine to load TX paths of all drivers with extra 
code, and that it's fine to effectively disable SG in the entire 
system just doesn't compute.

Is that a fair summary of the arguments?

I do not believe so.

My argument is about allowing XDP and full stack to work
synergistically: Fast path for known unicast traffic, and slow path for
BUM traffic without duplicating config such as ACLs and forcing a
specific design (such as forcing all programs in the XDP Rx path which
does not work for all traffic patterns). For example, if I am willing to
trade a few cycles of over head (redirect processing) for a simpler
overall solution then I should be to do that. Fast path with XDP is
still faster than the full host stack for known unicast traffic.