Generally, multiprocessor real-time scheduling algorithm fall into two basic approaches, partitioned and global. The hybrid solution that we proposed applies the partitioned scheduling approach to the task set until all processors have been filled. The remaining tasks are then scheduled using the global scheduling approach. The idea of a hybrid scheduling approach to ameliorate limitations of partitioned and global approaches. Studies have shown that most prior research on hybrid multiprocessor real-time scheduling has been confined to hard and soft real-time tasks. In fact, the implementation of hybrid approach and the performance of such algorithms in comparison to partitioned and global approaches have not been fully answered by previous studies. This paper performs experimental evaluation of our proposed hybrid multiprocessor scheduling approach, R-BOUND-MP-NFRNS and RM-US (m/3m-2) with multiprocessor response time test, with one of the best scheduling approach from partitioned and global scheduling approaches. The evaluation is based on simulation experiments using videophone application and Cruise Control with Collision Avoidance (CCCA) case studies that mixes real-time tasks of different criticality. The experimental results have presented in terms of three metrics or in other words, performance measurement parameters, namely deadline satisfaction ratio, least system utilization and preemption density (overhead ratio). Based on these three metrics, the proposed hybrid scheduling approach achieved higher percentage compare to the other two approaches. This indicates that such a hybrid scheduling approach is a viable alternative to use in multiprocessor systems and for best scheduled constrained deadline periodic tasks where timing constraints known as weakly hard.
Evaluation of the Proposed Hybrid Multiprocessor Real-Time Scheduling Approach with Partitioned and Global Approaches
