Cooperative Scheduling

Truly preemptive behavior in a system is not always acceptable especially in safety critical systems. Cooperative scheduling (aka deferred preemption) is used to splits tasks into slots. Interestingly enough, deferred preemption may lead to increased schedulabiliy of the system primary because the mutual exclusion is achieved via non-preemption and the task computabilty time tends to...

Release Jitter and Timer Granuality

Normally, perodic tasks within the system do not suffer release jitter, however the system may have some granularity on the timer in which case there is some release jitter e.g. if a task is released every 15 ms but the implementation restricts granularity of the system timer to 10 ms, the periodic task will run...

Release Jitter

In real-time systems, release jitter occurs when the task's arrival is not the same as when the task is released. This is very common issue for distributed systems. Suppose you have two tasks: one periodic and one sporadic . The periodic task () releases the sporadic task on another processor. We could attempt to model...