[oralty]

epoll (and even kqueue) is not aio and was never intended as such. While epoll had some early snafus, those have long been fixed (offering ET and LT) and it works well for its intended purpose (io readiness). This (io_uring) is more for a thing like Windows overlapped IO and "unix" (incl FreeBSD) aio. AIO on linux is yet a separate set of syscalls (io_*) and has since day one in the 2.5 days been pretty much a useless joke, very limited in scope (O_DIRECT only).

kqueue is neither epoll nor aio but a common queueing interface for events, which includes io readiness and aio completion as separate types. Linux prefers to split these as different types of fds. FWIW, this wasn't due to obliviousness of the existing design - https://yarchive.net/comp/linux/event_queues.html.

Honestly your comment sounds very like a regurgitated old and somewhat outdated Bryan Cantrill rant.

[gpderetta]

The link doesn't explain much. The only argument that Linus has on kqueue is that is overengineered. Then it goes on a long multi message rant in how having multiple queues is insane.

Luckily, in the end epoll ended up supporting multiple queues at least.

I do believe that ET is good though.