The previously reported on patches providing a ~5% improvement for UDP/IPv6 is now queued in the networking subsystem's net-next codebase ahead of the Linux 5.18 merge window opening around the end of March.
That UDP IPv6 work is summed up in this merge :
Shed some weight from udp/ipv6. Zerocopy benchmarks over dummy showed ~5% tx/s improvement, should be similar for small payload non-[zero copy] cases.
The performance comes from killing 4 atomics and a couple of big struct memcpy/memset. 1/10 removes a pair of atomics on dst refcounting for cork->skb setup, 9/10 saves another pair on cork init. 5/10 and 8/10 kill extra 88B memset and memcpy respectively.
Linux 5.18 stable in turn should be out around the end of May with these optimization patches and a whole lot more.