List Heuristic Scheduling Algorithms for Distributed Memory Systems with Improved Time Complexity

We present a compile time list heuristic scheduling algorithm called Low Cost Critical Path algorithm (LCCP) for the distributed memory systems. LCCP has low scheduling cost for both homogeneous and heterogeneous systems. In some recent papers list heuristic scheduling algorithms keep their scheduling cost low by using a fixed size heap and a FIFO, where the heap always keeps fixed number of tasks and the excess tasks are inserted in the FIFO. When the heap has empty spaces, tasks are inserted in it from the FIFO. The best known list scheduling algorithm based on this strategy requires two heap restoration operations, one after extraction and another after insertion. Our LCCP algorithm improves on this by using only one such operation for both the extraction and insertion, which in theory reduces the scheduling cost without compromising the scheduling performance. In our experiment we compare LCCP with other well known list scheduling algorithms and it shows that LCCP is the fastest among all.