Fault-Secure Scheduling of Arbitrary Task Graphs to Multiprocessor Systems

In this paper, we propose new scheduling algorithms to achieve fault security in multiprocessor systems. We consider scheduling of parallel programs represented by directed acyclic graphs with arbitrary computation and communication costs. A schedule is said to be 1-fault-secure if the system either produces correct output for a parallel program or it detects the presence of any single fault in the system. Although several 1-fault-secure scheduling algorithms have been proposed so far, they can all only be applied to a class of tree-structured task graphs with a uniform computation cost. In contrast, the proposed algorithms can generate a 1-fault-secure schedule for any given task graph with arbitrary computation costs. Applying the new algorithms to two kinds of practical task graphs (Gaussian elimination and LU-decomposition), we conduct simulations. Experimental results show that the proposed algorithms achieves 1-fault security at the cost of small increase in schedule length.