Task Assignment Algorithms for Two-type Heterogeneous Multiprocessors

Consider the problem of assigning implicit-deadline sporadic tasks on a heterogeneous multiprocessor platform comprising two different types of processors - such a platform is referred to as two-type platform. We present two linearithmic time-complexity algorithms, SA and SA-P, each providing the following guarantee. For a given two-type platform and a given task set, if there exists a feasible task-to-processor-type assignment such that tasks can be scheduled to meet deadlines by allowing them to migrate only between processors of the same type, then (i) using SA, it is guaranteed to find such a feasible task-to-processor-type assignment where the same restriction on task migration applies but given a platform in which processors are 1 + alpha/2 times faster and (ii) SA-P succeeds in finding a feasible task-to-processor assignment where tasks are not allowed to migrate between processors but given a platform in which processors are 1 + alpha times faster, where 0 < alpha <= 1. The parameter alpha is a property of the task set - it is the maximum utilization of any task which is less than or equal to 1.