You still need async (or an event loop model) because otherwise your threads will block waiting for the io_uring result when they could be put to better use (na

You still need async (or an event loop model) because otherwise your threads will block waiting for the io_uring result when they could be put to better use (namely submitting new io_uring jobs or conveying the results of completed ones). Note that the io_uring approach isn't too different (just more universalized) than how Windows has always implemented async operations (with overlapped and io completion ports). Code written for that environment originally just used the event loop model but it's easier/better ergonomics to wrap it in async and use that instead (e.g. how C#'s async/await works) because you can avoid callback hell, state passing, etc. and just write code "linearly" with cooperative yield points invisibly stashing and retrieving the "stack" for you.