On: How to think about async/await in Rust

[hot_gril]

Yeah, async is a type of greenthreading.

[metaltyphoon → hot_gril]

When I think of green threads / fibers, its threading handled in user space. Where a stack is starts small and it can grow and its managed by the language’s runtime.

[hu3 → hot_gril]

When I read async, I think about an event loop in a single thread.

Meanwhile when I read greenthreading, I think of lightweight threads like goroutines or Java's virtual threads.

Am I wrong?

[hot_gril → hu3]

Right. Both of them are running on a single OS thread with application-layer context switching. Async's form of context switching is the event loop, greenthreading's is something analogous to OS threads.

Maybe it's inaccurate to say async is a type of greenthreading and better to say it's a form of application-layer context-switching comparable to greenthreading.