Theoretically, Rust can be as fast as C/C++ as long as you dive into unsafe when necessary, or skip string like UTF-8 string. However, a lot of the upside for using Rust will be gone as well, which will not make using Rust as compelling as in other domains. And when using Rust, people will probably incline to use more idiomatic Rust, which will be a bit slower. Thus I would say you would expect the actual Rust code you see will be to around 6us in scale, that is, a bit slower but still comparable to C/C++, at the same time with much better robustness (much fewer crashes).