Recent trends and advancement in including more diverse and heterogeneous hardware in High-Performance Computing is challenging software developers in their pursuit for good performance and numerical stability. The well-known maxim "software outlives hardware" may no longer necessarily hold true, and developers are today forced to re-factor their codebases to leverage these powerful new systems. CFD is one of the many application domains affected. In this paper, we present Neko, a portable framework for high-order spectral element flow simulations. Unlike prior works, Neko adopts a modern object-oriented approach, allowing multi-tier abstractions of the solver stack and facilitating hardware backends ranging from general-purpose processors down to exotic vector processors and FPGAs. We show that Neko's performance and accuracy are comparable to NekRS, and thus on-par with Nek5000's successor on modern CPU machines. Furthermore, we develop a performance model, which we use to discuss challenges and opportunities for high-order solvers on emerging hardware.
@article{arxiv.2107.01243,
title = {Neko: A Modern, Portable, and Scalable Framework for High-Fidelity Computational Fluid Dynamics},
author = {Niclas Jansson and Martin Karp and Artur Podobas and Stefano Markidis and Philipp Schlatter},
journal= {arXiv preprint arXiv:2107.01243},
year = {2021}
}