Go-the-language does not have a preemptive scheduler, just guarantees about how various means of synchronization interact. In fact, Go-the-implementation is on

Go-the-language does not have a preemptive scheduler, just guarantees about how various means of synchronization interact. In fact, Go-the-implementation is only partially preemptive, I believe: in addition to calls into the runtime, calling any function can now be a scheduling event. But if you have a tight loop with no function calls (just arithmetic, perhaps), that goroutine will not yield control. A true preemptive scheduler would be able to take control from that goroutine.