Implicit Low-Order Unstructured Finite-Element Multiple Simulation Enhanced by Dense Computation using OpenACC

摘要

In this paper, we develop a low-order three-dimensional finite-element solverfor fast multiple-case crust deformation analysis on GPU-based systems. Basedon a high-performance solver designed for massively parallel CPU based systems,we modify the algorithm to reduce random data access, and then insert OpenACCdirectives. The developed solver on ten Reedbush-H nodes (20 P100 GPUs)attained speedup of 14.2 times from 20 K computer nodes, which is highconsidering the peak memory bandwidth ratio of 11.4 between the two systems. Onthe newest Volta generation V100 GPUs, the solver attained a further 2.45 timesspeedup from P100 GPUs. As a demonstrative example, we computed 368 cases ofcrustal deformation analyses of northeast Japan with 400 million degrees offreedom. The total procedure of algorithm modification and portingimplementation took only two weeks; we can see that high performanceimprovement was achieved with low development cost. With the developed solver,we can expect improvement in reliability of crust-deformation analyses bymany-case analyses on a wide range of GPU-based systems.