Sridhar Samudrala <sridhar.samudr...@intel.com> writes: > This patch series introduces XDP_SKIP_BPF flag that can be specified > during the bind() call of an AF_XDP socket to skip calling the BPF > program in the receive path and pass the buffer directly to the socket. > > When a single AF_XDP socket is associated with a queue and a HW > filter is used to redirect the packets and the app is interested in > receiving all the packets on that queue, we don't need an additional > BPF program to do further filtering or lookup/redirect to a socket. > > Here are some performance numbers collected on > - 2 socket 28 core Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz > - Intel 40Gb Ethernet NIC (i40e) > > All tests use 2 cores and the results are in Mpps. > > turbo on (default) > --------------------------------------------- > no-skip-bpf skip-bpf > --------------------------------------------- > rxdrop zerocopy 21.9 38.5 > l2fwd zerocopy 17.0 20.5 > rxdrop copy 11.1 13.3 > l2fwd copy 1.9 2.0 > > no turbo : echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo > --------------------------------------------- > no-skip-bpf skip-bpf > --------------------------------------------- > rxdrop zerocopy 15.4 29.0 > l2fwd zerocopy 11.8 18.2 > rxdrop copy 8.2 10.5 > l2fwd copy 1.7 1.7 > ---------------------------------------------
You're getting this performance boost by adding more code in the fast path for every XDP program; so what's the performance impact of that for cases where we do run an eBPF program? Also, this is basically a special-casing of a particular deployment scenario. Without a way to control RX queue assignment and traffic steering, you're basically hard-coding a particular app's takeover of the network interface; I'm not sure that is such a good idea... -Toke
