busypoll not work

[hi-glenn]

official example https://github.com/xdp-project/bpf-examples/tree/main/AF_XDP-example

command

taskset -c 16 ./xdpsock -i enp5s0f1 -q 0 -r -N -Q -B -b 64

work ok on the following environment:

OS:
Ubuntu 23.04 
Linux 6.2.0-39-generic

NIC:
driver: ixgbe
version: 6.2.0-39-generic

work fail on the following environment:

OS:
Ubuntu 24.04.3 LTS 
Linux 6.14.0-37-generic

NIC:
driver: ixgbe
version: 6.14.0-37-generic

---

the phenomenon when fail：

1. when use trex traffgen send packets at high speed( such as 10Mpps ), will use 2 cpu core, core16 and core40

taskset -c 16 ./xdpsock -i enp5s0f1 -q 0 -r -N -Q -B -b 64

2. when use the following cmd, though use only a core, but process fewer pkts, trex traffgen send packets at low speed( such as 1Mpps ). when trex traffgen send packets at high speed ( such as 10Mpps ), the program will get stuck and not process any package.

taskset -c 40 ./xdpsock -i enp5s0f1 -q 0 -r -N -Q -B -b 64