Suspending a running thread
The execution of a running thread is temporarily suspended whenever the microkernel is entered as the result of a kernel call, exception, or hardware interrupt. A scheduling decision is made whenever the execution state of any thread changes — it doesn't matter which processes the threads might reside within. Threads are scheduled globally across all processes.
Normally, the execution of the suspended thread will resume, but the scheduler will perform a context switch from one thread to another whenever the running thread:
- is blocked
- is preempted