Edf scheduling on heterogeneous multiprocessors

• Authors: Sanjoy K. Baruah;Shelby Hyatt Funk
• Venue: Edf scheduling on heterogeneous multiprocessors
• Year: 2004

The goal of this dissertation is to expand the types of systems available for real-time applications. Specifically, this dissertation introduces tests that ensure jobs will meet their deadlines when scheduled on a uniform heterogeneous multiprocessor using the Earliest Dead line First (EDF) scheduling algorithm, in which jobs with earlier deadlines have higher priority. On uniform heterogeneous multiprocessors, each processor has a speed s, which is the amount of work that processor can complete in one unit of time. Multiprocessor scheduling algorithms can have several variations depending on whether jobs may migrate between processors—i.e., if a job that starts executing on one processor may move to another processor and continue executing. This dissertation considers three different migration strategies: full migration, partitioning, and restricted migration. The full migration strategy applies to all types of job sets. The partitioning and restricted migration strategies apply only to periodic tasks, which generate jobs at regular intervals. In the full migration strategy, jobs may migrate at any time provided a job never executes on two processors simultaneously. In the partitioning strategy, all jobs generated by a periodic task must execute on the same processor. In the restricted migration strategy, different jobs generated by a periodic task may execute on different processors, but each individual job can execute on only one processor. The thesis of this dissertation is: Schedulability tests exist for the Earliest Deadline First (EDF) scheduling algorithm on heterogeneous multiprocessors under different migration strategies including full migration, partitioning, and restricted migration. Furthermore, these tests have polynomial-time complexity as a function of the number of processors (m) and the number of periodic tasks (n). (1) The Schedulability test with full migration requires two phases: an O (m) one-time calculation, and an O (n) calculation for each periodic task set. (2) The Schedulability test with restricted migration requires an O (m + n) test for each multiprocessor/task set system. (3) The Schedulability test with partitioning requires two phases: a one-time exponential calculation, and an O (n) calculation for each periodic task set.