A New Task Model and Utilization Bound for Uniform Multiprocessors
نویسنده
چکیده
This paper introduces a new model for describing jobs and tasks for real-time systems. Using this model can improve utilization bounds on uniform multiprocessors, in which each processor has an associated speed. Traditionally, a job executing on a processor of speed s for t units of time will perform s × t units of work. However, this uniform scaling only occurs if tasks are completely CPU bound. In practice, tasks will have some portion of execution that does not scale with the increased CPU speed. Dividing the execution into CPU execution and fixed execution allows the scheduler to place CPU bound tasks on faster processors, as they can take full advantage of the extra speed. This model is used in a new utilization test for EDF scheduling with restricted migration, r-EDF, in which tasks are allowed to migrate, but only at job boundaries. The test is proven to be better than the existing r-EDF test for uniform multiprocessors.
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