Evaluating HPX and Kokkos on RISC-V using an Astrophysics Application Octo-Tiger

TL;DR

This paper evaluates the performance of the Octo-Tiger astrophysics application running on RISC-V systems, highlighting promising results and potential improvements with dedicated ISA extensions for high-performance computing.

Contribution

It reports the porting and performance assessment of Octo-Tiger on RISC-V, emphasizing the need for ISA extensions to enhance HPC application performance.

Findings

Octo-Tiger shows promising performance on RISC-V systems.

Good scaling observed despite limited hardware capabilities.

Potential for significant improvements with dedicated ISA extensions.

Abstract

In recent years, computers based on the RISC-V architecture have raised broad interest in the high-performance computing (HPC) community. As the RISC-V community develops the core instruction set architecture (ISA) along with ISA extensions, the HPC community has been actively ensuring HPC applications and environments are supported. In this context, assessing the performance of asynchronous many-task runtime systems (AMT) is essential. In this paper, we describe our experience with porting of a full 3D adaptive mesh-refinement, multi-scale, multi-model, and multi-physics application, Octo-Tiger, that is based on the HPX AMT, and we explore its performance characteristics on different RISC-V systems. Considering the (limited) capabilities of the RISC-V test systems we used, Octo-Tiger already shows promising results and good scaling. We, however, expect that exceptional hardware support based on dedicated ISA extensions (such as single-cycle context switches, extended atomic operations, and direct support for HPX's global address space) would allow for even better performance results.