Static-priority Scheduling on Multiprocessors

Doktorsavhandling, 2003

This thesis deals with the problem of scheduling a set of tasks to meet deadlines on a computer with multiple processors. Static-priority scheduling is considered, that is, a task is assigned a priority number that never changes and at every moment the highest-priority tasks that request to be executed are selected for execution. The performance metric used is the capacity that tasks can request without missing a deadline. It is shown that every static-priority algorithm can miss deadlines although close to 50% of the capacity is requested. The new algorithms in this thesis have the following performance. In periodic scheduling, the capacity that can be requested without missing a deadline is: 33% for migrative scheduling and 50% for non-migrative scheduling. In aperiodic scheduling, many performance metrics have been used in previous research. With the aperiodic model used in this thesis, the new algorithms in this thesis have the following performance. The capacity that can be requested without missing a deadline is: 50% for migrative scheduling and 31% for non-migrative scheduling.