Evaluation of the Partitioned Global Address Space (PGAS) model for an inviscid Euler solver

TL;DR

This paper evaluates the performance of the PGAS model using Unified Parallel C for fluid dynamics simulations, comparing it with MPI across various HPC clusters and an Intel Xeon Phi, highlighting ease of development and performance trade-offs.

Contribution

It provides an empirical comparison of UPC and MPI for fluid dynamics, demonstrating UPC's ease of use and competitive performance on diverse HPC systems.

Findings

UPC is easier to develop than MPI.

Performance of UPC is comparable to MPI on most clusters.

UPC outperforms MPI on Intel Xeon Phi.

Abstract

In this paper we evaluate the performance of Unified Parallel C (which implements the partitioned global address space programming model) using a numerical method that is widely used in fluid dynamics. In order to evaluate the incremental approach to parallelization (which is possible with UPC) and its performance characteristics, we implement different levels of optimization of the UPC code and compare it with an MPI parallelization on four different clusters of the Austrian HPC infrastructure (LEO3, LEO3E, VSC2, VSC3) and on an Intel Xeon Phi. We find that UPC is significantly easier to develop in compared to MPI and that the performance achieved is comparable to MPI in most situations. The obtained results show worse performance (on VSC2), competitive performance (on LEO3, LEO3E and VSC3), and superior performance (on the Intel Xeon Phi).