Challenges of applying an embedded domain specific language for performance portability to Earth system models

Weather and climate modeling, reliant on substantial computational resources, faces challenges of escalating
resource demands and energy consumption as problem sizes and model complexity increase. Leveraging
Graphics Processing Units (GPUs) for accelerated simulations demands performance portability across diverse
High Performance Computing (HPC) architectures. The concept of embedded Domain Specific Language
(eDSL) emerges as a lightweight solution, aiming to streamline GPU utilization without extensive code rewrites
and to enhance code portability across HPC architectures. This study explores the practical implementation of
an eDSL within the Icosahedral Nonhydrostatic (ICON) weather and climate model, primarily written in Fortran.
Our evaluation contrasts eDSL utilization within ICON against other Earth system models, with particular
emphasis on three-dimensional mass transport, or advection. Through assessing the eDSL’s efficectiveness in
various models, especially its application in the ParFlow and EULAG models, insights into its potential for
ICON emerge. While the eDSL presents a promising avenue for performance portability, challenges in adapting
Fortran-based codes, GPU support, and resource allocation underscore the need for necessity for thorough
planning and resource allocation in model development endeavors. Overall, the eDSL offers a viable pathway
for harnessing GPU acceleration while mitigating the complexities of code portability across diverse HPC
architectures, essential for advancing weather and climate modeling capabilities.