tw061023

These are microbenchmarks, thoroughly optimized to the point some of them are written almost completely in SSE intrinsics.

I would expect Rust to be 2x-3x slower in real production code, solely due to approach to memory allocation.

aw1621107

> solely due to approach to memory allocation

Would you mind elaborating on this? I don't think I've read anything (yet?) that touches on performance differences due to that particular aspect of the languages.

tw061023

Long story short, heap allocation is painfully slow. Any sort of malloc will always be slower than a custom pool or a bump allocator, because it has a lot more context to deal with.

Rust makes it especially hard to use custom allocators, see bumpalo for example [0]. To be fair, progress is being made in this area [1].

Theoretically one can use a "handle table" as a replacement for pools, you can find relevant discussion at [2].

[0] https://github.com/fitzgen/bumpalo

[1] https://github.com/rust-lang/rust/issues/32838

[2] https://news.ycombinator.com/item?id=36353145

Edit: formatting.