On Sat, Mar 2, 2024 at 2:40 AM Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> wrote: > > Maciej Fijalkowski wrote: > > On Wed, Feb 28, 2024 at 07:05:56PM +0800, Yunjian Wang wrote: > > > This patch set allows TUN to support the AF_XDP Tx zero-copy feature, > > > which can significantly reduce CPU utilization for XDP programs. > > > > Why no Rx ZC support though? What will happen if I try rxdrop xdpsock > > against tun with this patch? You clearly allow for that. > > This is AF_XDP receive zerocopy, right? > > The naming is always confusing with tun, but even though from a tun > PoV this happens on ndo_start_xmit, it is the AF_XDP equivalent to > tun_put_user. > > So the implementation is more like other device's Rx ZC. > > I would have preferred that name, but I think Jason asked for this > and given tun's weird status, there is something bo said for either. > >From the the view of the AF_XDP userspace program, it's the TX path, and as you said it happens on the TUN xmit path as well. When using with a VM, it's the RX path. So TX seems better. Thanks
