Posted this the other day but the whole musl allocator thing seems to be well known [0]

[0]: https://news.ycombinator.com/item?id=45143347

Musl's allocator being awful is pretty well known, though mostly in that it's absolutely awful in multithreaded context. TFA points out that musl has a bunch of other noticeably slower functions, which is less well known (though they're also slower by a smaller factor, and they don't worsen as your parallelism increases).