Adaptive Scheduling Mechanisms for SPARTAs

Scheduling involves deciding when to run a given task, how much time to allocate to it, and in a multiprocessing enironment where to run it. In this paper we focus on scheduling mechanisms for Soft PArallel Real-Time Applications (SPARTAs). The key element in the mechanisms we propose is their ability to adapt to a changing set of constraints allowing the application to adapt to a dynamic environment. These mechanisms take advantage of the fact that the real world can be modeled via continuous functions and that the derivative of a task's execution time is small. We present three mechanisms, one intended to provide guarantees similar to worst case scheduling, and two others designed to provided nearer to average case performance with analyzable deadline miss rates. We analyze the proposed scheduling policies and provide experimental results comparing their performance.sity of Maryland. The Government has certain rights in this material. Any opinions, ndings, and conclusions of recommendations expressed in this material are of the authors and do not necessarily reeect the views of the above agencies.