Towards Order-Preserving and Zero-Copy Communication on Shared Memory for Large Scale Simulation

Parallel simulation generally needs efficient, reliable and order-preserving communication. In this article, a zero-copy, reliable and order-preserving intra-node message passing approach named ZeROshm is proposed. This mechanism partitions shared memory into segments assigned to processes for receiving messages. Each segment consists of two levels of index L1 and L2 that recordes the order of messages in the host segment, and the processes also read from and write to the segments directly according to the indexes, thereby eliminating allocating and copying buffers. As experimental results show, ZeROshm exhibits nearly equivalent performance to message passing interface (MPI) for small message and superior performance for large message. Specifically, ZeROshm costs less time by 43%, 40% and 55% respectively in pure communication, communication with contention and real PHOLD simulation within a single node. Additionally, in hybrid environment, the combination of ZeROshm and MPI also shorten the execution time of PHOLD simulation by about 42% compared to pure MPI.