At ISC High-Performance 2024, we present Neko – a portable framework for high-fidelity spectral element flow simulations. Unlike prior work, Neko adopts a modern object-oriented Fortran 2008 approach, allowing multi-tier abstractions of the solver stack and facilitating various hard- ware backends ranging from general-purpose processors, accelerators down to exotic vector processors and Field Programmable Gate Arrays (FPGAs) via Neko’s device abstraction layer. Focusing on Neko’s performance and exascale readiness, we outline the optimisation and algorithmic work necessary to ensure scalability and performance portability across a wide range of platforms. Finally, we present performance measurements on a wide range of accelerated computing platforms, including the EuroHPC pre-exascale systems LUMI and Leonardo, where Neko achieves excellent parallel efficiency for an extreme-scale direct numerical simulation (DNS) of turbulent thermal convection using up to 80% of the entire LUMI supercomputer.

If you have a workshop pass, please come hear about application development in the European HPC Centres of Excellence including CEEC!

“this ISC workshop has been organised to provide a forum to consider common challenges, ideas, solutions, and opportunities from the point of view of HPC applications developers preparing for exa-scale.”