Performance Emulation of Cell-Based AMR Cosmology Simulations

Cosmological simulations are highly complicated, and it is time-consuming to redesign and reimplement the code for improvement. Moreover, it is a risk to implement any idea directly in the code without knowing its effects on performance. In this paper, we design an emulator for cell-based AMR (adaptive mesh refinement) cosmology simulations, in particular, the Adaptive Refinement Tree (ART) application. ART is an advanced "hydro+N-body" simulation tool integrating extensive physics processes for cosmological research. The emulator is designed based on the behaviors of cell-based AMR cosmology simulations, and quantitative performance models are built toward the design of the emulator. Our experiments with realistic cosmology simulations on production supercomputers indicate that the emulator is accurate. Moreover, we evaluate and compare three different load balancing schemes for cell-based cosmology simulations via the emulator. The comparison results provide us useful insight into the performance and scalability of different load balance schemes.