Predictive modeling of the performance of asynchronous iterative methods

Asynchronous algorithms may increase the performance of parallel applications on large-scale HPC platforms due to decreased dependence among processing elements. This work investigates strategies for implementing asynchronous hybrid parallel MPI-OpenMP iterative solvers. Seven different implementations are considered, and results show that striking a balance between communication and computation that balances the number of iterations in each processing element benefits performance and solution quality. A predictive performance model that utilizes kernel density estimation to model the underlying probability density function to the collected data is then developed to optimize execution parameters for a given problem. For the majority of iteration executions, the performance model matches within about 6% of the empirical data. The different hybrid parallel implementations are examined further to find optimal parametric distributions whose parameters can be tuned to the problem at hand. The generalized extreme value distribution was selected based on a combination of quantitative and qualitative comparisons, and for the most of the iteration executions, the model matches the data within about 6.1%. Results from the parametric distribution model are examined along with results of the model on related problems, and possible further extensions to the predictive model are discussed.