Pipelining granularity optimization algorithm based on loop tiling
LIU Xiaoxian1,2,ZHAO Rongcai1,2,DING Rui1,2,LI Yanbing1,2
1. .Information Engineering University, Zhengzhou Henan 450002, China
2. State Key Laboratory of Mathematical Engineering and Advanced Computing, Zhengzhou Henan 450002, China
Abstract:When the pipelining loop has a great number of iterations, or the size of its body is large, but the number of available threads is small, the workload between two synchronizations of a thread is so heavy, which produces pretty low degree of parallelism. The traditional trade-off approach based on loop tiling cannot handle the above situation. To solve this problem, a pipelining granularity decreasing approach based on loop tiling was proposed. The optimal pipelining granularity was obtained by building the cost model for pipelining loop and a pipelining granularity optimizing algorithm was implemented. By measuring the wavefront loops of Finite Difference Relaxation (FDR) and the representative loops of Finite Difference Time Domain (FDTD), the loops show better performance improvement by using the proposed algorithm than the traditional one.