The github icon on the site directs to the author’s own page, and I couldn’t find any repository for the site, which makes me curious why do they even put the github link? Just for a follow?
Switching to non-default allocator does not always brings performance boost. It really depend on your workload, which requires profiling and benchmarking. But C/C++/Rust and other lower level languages should all at least be able to choose from these allocators. One caveat is binary size. Custom allocator does add more bytes to executable.
The root cause is AMD's bad support for rep movsb (which is a hardware problem). However, python by default has a small offset when reading memories while lower level language (rust and c) does not, which is why python seems to perform better than c/rust. It "accidentally" avoided the hardware problem.
Disclaimer: The title has been changed to "Rust std fs slower than Python!? No, it's hardware!" to avoid clickbait. However I'm not able to fix the title in HN.
Immutable doesn’t mean it cannot be updated. It just means that updates are happening without touching the same copy. This CoW-ish style is what they’re selling.