epoll isn’t very fast, kqueue is indeed much faster as a primitive.

MacOS’s implementation is an order of magnitude or more slower than (say) FreeBSD though, so its not a valid comparison that the syscall simply exists.

Another example of a syscall performing differently would be gettimeofday() in OpenBSD vs linux, its an extremely cheap operation in Linux but quite costly in OpenBSD despite being identical at the kernel boundary.

epoll is kinda slow compared to io_uring, I am typically getting double the perf just switching to uring.