Re: [PATCH bpf-next V3 0/6] bpf: New approach for BPF MTU handling

Jakub Kicinski
2020-10-13T23:07:29Z

On Tue, 13 Oct 2020 22:40:09 +0200 Jesper Dangaard Brouer wrote:
> > FWIW I took a quick swing at testing it with the HW I have and it did
> > exactly what hardware should do. The TX unit entered an error state
> > and then the driver detected that and reset it a few seconds later.
>
> The drivers (i40e, mlx5, ixgbe) I tested with didn't entered an error
> state, when getting packets exceeding the MTU. I didn't go much above
> 4K, so maybe I didn't trigger those cases.

You probably need to go above 16k to get out of the acceptable jumbo
frame size. I tested ixgbe by converting TSO frames to large TCP frames,
at low probability.