Research On Global Fp Scheduling Algorithm On Multiprocessor Platform

Real-time systems and people's lives becoming closer and closer, it is widely used in industrial control, network transmission, multimedia processing, and military and other fields. Initially people focus on real-time system of single-processor platform, an important reason for the high cost of the processor. With the emergence of the technology that integrate multiple processors on a single chip, more and more multi-processor applications is becoming popular; However, the theory that run correctly on a single processor platform can not simply be extended to multi-processor platform, so it is necessary to study the situation of multi-processor platform. Determine the schedulability of real-time systems reliability theory is the key theory of security, it ensures that any task set which meet the schedulability conditions will not miss their deadline. In this paper, we study the problem how to determine the schedulability of periodic task on real-time multi-processor platform.First, based on the Bertogna etc's thought to address the schedulability problem of periodic task with deadline-constrained scheduled by the global FP, further studies was made, we demonstrate that when the amount of the highest priority task was not more than the number of processors in the system, using the worst-case presented by Bertogna to compute the interference of the task with highest priority is too pessimistic,by analyzing characteristics of the highest priority periodic task scheduled by FP, a smaller upper bound of interference suffered from highest priority task was attained; then a tighter schedulability condition in which period task was scheduled with RM was attained.Then, based on the Baruah etc's thought of schedulability determination for arbitrary deadline sporadic task scheduled by DM, and the Baker's thought of schedulability determination for arbitrary deadline sporadic task scheduled by EDF, the schedulability problem of periodic task with arbitrary deadline scheduled by RM was studied. From the point of task missing deadline, analyzing the characteristics of active tasks, the necessary condition in which periodic task with arbitrary deadline must miss its deadline was attained. As long as the task set do not meet this necessary condition, we can guarantee arbitrary deadline periodic task set is schedulable.Finally, we design and implement the multi-processor platform, with which schedulability of deadline constrained periodic task set scheduled by RM could be compared; based on this experimental platform, we are using multiple sets of data (test mode, the number of processors, and the average task efficiency) to compare our improved test and FP test put forward by Bertogna etc, the results show that ours improved RM test detected more scheduled tasks set than Bertogna etc's test.