Parallel 3-D S(sub N) performance for DANTSYS/MPI on the Cray T3D

摘要

A data parallel version of the 3-D transport solver in DANTSYS has been in use on the SIMD CM-200's at LANL since 1994. This version typically obtains grind times of 150--200 nanoseconds on a 2,048 PE CM-200. The authors have now implemented a new message passing parallel version of DANTSYS, referred to as DANTSYS/MPI, on the 512 PE Cray T3D at Los Alamos. By taking advantage of the SPMD architecture of the Cray T3D, as well as its low latency communications network, they have managed to achieve grind times of less than 10 nanoseconds on real problems. DANTSYS/MPI is fully accelerated using DSA on both the inner and outer iterations. This paper describes the implementation of DANTSYS/MPI on the Cray T3D, and presents two simple performance models for the transport sweep which accurately predict the grind time as a function of the number of PE's and problem size, or scalability.