On Fri, May 28, 2021 at 11:25:56AM +0200, Toke Høiland-Jørgensen wrote: > Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> writes: > > > On Fri, 28 May 2021 10:55:58 +0200, Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > >> Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> writes: > >> > >> > In xsk mode, users cannot use AF_PACKET(tcpdump) to observe the current > >> > rx/tx data packets. This feature is very important in many cases. So > >> > this patch allows AF_PACKET to obtain xsk packages. > >> > >> You can use xdpdump to dump the packets from the XDP program before it > >> gets redirected into the XSK: > >> https://github.com/xdp-project/xdp-tools/tree/master/xdp-dump > > > > Wow, this is a good idea. > > > >> > >> Doens't currently work on egress, but if/when we get a proper TX hook > >> that should be doable as well. > >> > >> Wiring up XSK to AF_PACKET sounds a bit nonsensical: XSK is already a > >> transport to userspace, why would you need a second one? > > > > I have some different ideas. In my opinion, just like AF_PACKET can monitor > > tcp/udp packets, AF_PACKET monitors xsk packets is the same. > > But you're adding code in the fast path to do this, in a code path where > others have been working quite hard to squeeze out every drop of > performance (literally chasing single nanoseconds). So I'm sorry, but > this approach is just not going to fly. +1. Probably would be better for everyone if Xuan started a thread on list what is his need. > > What is your use case anyway? Yes, being able to run tcpdump and see the > packets is nice and convenient, but what do you actually want to use > this for? Just for debugging your application? System monitoring? > Something else? > > -Toke >
