The architecture of a real-time system determines how and when threads are processed. Two common architectures are the
control loop with polling
approach and the
model. In the control loop with polling
approach, the kernel executes an infinite loop, which polls the threads in a predetermined pattern. If a thread needs service, then it is processed. There are several variants to this approach, including
to ensure that each thread is guaranteed access to the processor. Figure 1.3 contains an illustration of the control loop with polling approach.