A network protocol is only a small component of a microservice in terms of affecting performance, by far the biggest difference is an in-process call vs network/IPC call. The latter is at least hundreds time slower due to how computers work [0].

I'm talking about a function call overhead only so if the actual processing takes more than a few milliseconds it stops being important.

[0] http://www.eecs.berkeley.edu/~rcs/research/interactive_laten...