usually with Rust impactful savings come from writing the Rust differently, not from doing hand-written assembly instead.
See stuff like https://davidlattimore.github.io/posts/2025/09/02/rustforge-...
This doesn't mean Rust is near perfect, it's just that your first move should be "how do I make the Rust better" and not "I need to drop into asm."
"We’d like to initialise our Vec in parallel, otherwise we’d have to wait for the main thread to fill the entire Vec with a placeholder value only to then have our threads overwrite those placeholder values."
Talk about overengineering :P Multithreaded vector initialisation instead of just...skipping it?