[Matthias247]

It will likely not help a lot, because syscall overhead is not the bottleneck - but the implementation of the actual syscalls is - which is very visible in the flamegraphs. Both sendmmsg/recvmmsg and io_uring only help with the syscall overhead, and therefore are not as helpful in improving efficiency as the the offloads which make the actual network stack more efficient.

Besides kernel supplied offloads, the thing which helps further is actually bypassing the kernel with AF_XDP or DPDK. But those techniques will have other challenges and limitations.