Improvements in PIC performance through sorting, caching, and dynamic load balancing

VORPAL has achieved an over quadrupling performance improvement through the introduction of sorting, caching, and dynamic load balancing. Particle sorting allows us to increase temporal locality of data structures, thus maximizing utilization of a computer’s cache. Manual caching of particle grid coordinates prevents redundant computation of these values which are needed during multiple steps in the particle update process. Dynamic load balancing continuously adjusts load distribution in a parallel environment to maximize the utilization across all processors. These optimization methods are controlled by cost minimizing functions that seek to find a balance between overhead in performing them and the performance improvement they provide.