UPC Architecture for High-Performance Computational Hydrodynamics

Abstract

In this paper, we developed a computational hydrodynamics (CHD) numerical model based on the Unified Parallel C (UPC) computing architecture. UPC is the extension of ISO C following the Partitioned Global Address Space (PGAS) architecture which harnesses the ease of programming of the shared memory paradigm while enabling the exploitation of data locality. UPC computing stores the data having the affinity with the corresponding computing thread in the local memory section which significantly improves the computational speedup. UPC requires a unique arrangement to achieve the optimal combination of programmability, portability, and performance scalability. The UPC-CHD model is currently governed by the unsteady, laminar, and incompressible Navier–Stokes (NS) equations with domain decomposition. The temporal term is discretized with the two-step explicit scheme from the Lax-Wendroff family of predictor–correctors. The convective fluxes are computed by the ROE scheme with the third-order upwind-biased algorithm, and the viscous terms are discretized with the second-order central differencing scheme. The calculations of the flux predictor and corrector are then distributed using a UPC work-sharing function, which is based on the single-program multiple-data approach (SPMD). The data structure together with the discretization is uniquely arranged for UPC architecture using blocked-cyclic techniques and affinity calculation algorithms. Three reference cases of laminar Blasius boundary layer, Poiseuille’s flow and Couette’s flow were simulated with UPC-CHD. The accuracy of these reference cases was first validated using the respective analytical solution, which was followed by evaluating the model’s computational performance with an SGI UV-2000 server of 100 cores. The speedup results confirm the high efficiency of the proposed computer architecture as compared to other existing ones. With proper optimization, the speed up of the UPC-CHD model is almost 56 times and 5 times faster than the sequential version and sole-UPC version without optimization, respectively.