It’s a huge shame that Linux never merged NetMap (FreeBSD did but it remains an out-of-tree patch set with Linux, and I think it only works with some Intel NICs there). NetMap lets you map descriptor rings directly into userspace, but also allows the NIC to remain usable by the kernel.
well DPDK has the KNI, which lets you hit the kernel stack. and like i say in there, i’m fairly certain you can dispatch different NIC hwqueues to kernel vs dpdk–i’ve not seen this done, but it seems wholly technically feasible.
three cheers for netbsd, though!