On Mon, Jun 26, 2023 at 3:00 PM Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx> wrote: > > Stanislav Fomichev <sdf@xxxxxxxxxx> writes: > > > On Fri, Jun 23, 2023 at 4:29 PM Vinicius Costa Gomes > > <vinicius.gomes@xxxxxxxxx> wrote: > >> > >> Stanislav Fomichev <sdf@xxxxxxxxxx> writes: > >> > >> > Have a software-based example for kfuncs to showcase how it > >> > can be used in the real devices and to have something to > >> > test against in the selftests. > >> > > >> > Both path (skb & xdp) are covered. Only the skb path is really > >> > tested though. > >> > > >> > Cc: netdev@xxxxxxxxxxxxxxx > >> > Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx> > >> > >> Not really related to this patch, but to how it would work with > >> different drivers/hardware. > >> > >> In some of our hardware (the ones handled by igc/igb, for example), the > >> timestamp notification comes some time after the transmit completion > >> event. > >> > >> From what I could gather, the idea would be for the driver to "hold" the > >> completion until the timestamp is ready and then signal the completion > >> of the frame. Is that right? > > > > Yeah, that might be the option. Do you think it could work? > > > > For the skb and XDP cases, yeah, just holding the completion for a while > seems like it's going to work. > > XDP ZC looks more complicated to me, not sure if it's only a matter of > adding something like: [..] > void xsk_tx_completed_one(struct xsk_buff_pool *pool, struct xdp_buff *xdp); > > Or if more changes would be needed. I am trying to think about the case > that the user sent a single "timestamp" packet among a bunch of > "non-timestamp" packets. Since you're passing xdp_buff as an argument I'm assuming that is suggesting out-of-order completions? The completion queue is a single index, we can't do ooo stuff. So you'd have to hold a bunch of packets until you receive the timestamp completion; after this event, you can complete the whole batch (1 packet waiting for the timestamp + a bunch that have been transmitted afterwards but were still unacknowleged in the queue). (lmk if I've misinterpreted)
