SSSP on GPU without atomic operation

Graph is a general theoretical model in many large scale data-driven applications. SSSP (Single Source Shortest Path) algorithm is a foundation for most important algorithms and applications. GPU remains its mainstream station in high performance computing with heterogeneous architecture computers. Because of the high parallelization of the GPU threads, the distances of the vertices of the GPU are updated by atomic operations to avoid the read and write errors. Most atomic operations are unnecessary since the read-write conflicts are rare in large graph. However, without atomic operations the result accuracy can’t be guaranteed. The atomic operations take large part of the running time of the program. To improve the performance of SSSP on GPU, we proposed an algorithm with data block iterations instead of atomic operations. The algorithm not only gets a high speed-up but also guarantees the accuracy of the result. Experimental results show that this SSSP algorithm gained a speedup of three times than the serial algorithm on CPU and more than ten times than the parallel algorithm on GPU with atomic operation.