[haxen]

I think the distinction is pretty clear: either the mechanism requires cooperation by the application thread (which typically initiates the yield at a compiled-in, predefined point), or it doesn't and the runtime environment preempts it from the outside.

Virtual threads are of the former kind. (At least as long as we don't involve the forced preemption feature).

[pron]

Virtual threads are not cooperative, and OS threads that process transactions are also normally preempted almost exclusively at syscalls initiated by the thread, but I can't stop you from calling them that. The important thing to remember is that you program them like OS threads or Go goroutines or Erlang processes ("interleaving can happen anywhere unless I forbid it") and not like async/await or Kotlin's coroutines or asynchronous code or Windows 3.0 ("interleaving can only happen at certain allowed, known points"), whatever you want to call these two styles.

[haxen]

I concur with your point about the programming model and style, but I do also maintain that "cooperative" vs. "preemptive" is not about that difference. It is a technical difference on how the system interleaves threads and whether it needs cooperation from the code running on them, and not on the programming model and critical sections.

For the distinction you have in mind, I see the terms "colored" vs. "non-colored functions" to be used the most, and they are both within the "cooperative multithreading" space.