Wow. Perhaps I should be embarrassed, but I mentally filled in "30 GB/s" instead of 3 GB/s. I thought Rust was mostly neck and neck with C. I see now why a lot of fellows responded in a defensive way.
What's it doing to be so much slower? That's shocking. I may not enjoy Rust, but I do respect its ability to approach C++ performance.
At the very least, the itoap crate being used there does divisions by and comparisons to powers of 10 as part of stringifying integers, which the C and ASM versions don't seem to be doing. A crate with a function for stringifying arbitrary integers cannot take advantage of the fact that it's going to be used for stringifying consecutive integers, as an inlined solution can.
Not really. This is a hyper optimised microbenchmark. The actual work being done is so trivial that any "overhead" is really significant and you can get order of magnitude speedups by doing arcane things with caches, eliminating tiny inefficiencies and so on.
Complete speculation, but I think you'd find that's true for most problems. Very little CPU time is spent on the business logic, and the rest is overhead.
I'm curious, how did rust affect you so badly that you hate it so much? If it's just silly people suggesting it everywhere I think you have some personal issues you need to resolve, language choice isn't something to get emotional about.
What's it doing to be so much slower? That's shocking. I may not enjoy Rust, but I do respect its ability to approach C++ performance.