If it's still running on more than a single core, and your students want it to go faster, aligning the work to cpus will almost certainly be useful.

I saw you mentioned windows development elsewhere. You might be interested to know that Microsoft pionered Receive Side Scaling and Send Side Scaling. If you try your proxy out on Windows, be sure to hook into those systems there.

The less work your proxy does, the more important avoiding cross core communication is.

Thanks for the write up. So the first version was synchronous, second version was using epoll and third one will be use io_uring?