I know the rough high-level, and it's not necessarily WSL. POSIX programming does stuff differently than NT programming, the main or at least most noticeable de

I know the rough high-level, and it's not necessarily WSL. POSIX programming does stuff differently than NT programming, the main or at least most noticeable design pattern being frequent process creation and lots of small IPC calls. On Windows this is slow. POSIX programmers also tend to set up directory structures with many small files. This is not necessarily slow on NTFS, but Windows' implementation seems to have many pathological edge cases. There is also of course some translation overhead. That may be in the driver filter stack, though that is decently designed (it's close to having filter code pass over zero-copy state).