An Efficient Backup-Overloading for Fault-Tolerant Scheduling of Real-Time Tasks

Many time-critical applications require dynamic scheduling with predictable performance. Tasks corresponding to these applications have deadlines to be met despite the presence of faults. In this paper, we propose a technique called dynamic grouping, to be used with backup overloading in a primary-backup based fault-tolerant dynamic scheduling algorithm in multiprocessor real-time systems. In dynamic grouping, the processors are dynamically grouped into logical groups in order to achieve e cient overloading of backups, thereby improving the schedulability. We compare the performance of dynamic grouping with that of static grouping and no-grouping schemes through extensive simulation studies and show the e ectiveness of dynamic grouping.