Exploring the Performance Fluctuations of HPC Workloads on Clouds

Clouds enable novel execution modes often supported by advanced capabilities such as autonomic schedulers. These capabilities are predicated upon an accurate estimation and calculation of runtimes on a given infrastructure. Using a well understood high-performance computing workload, we find strong fluctuations from the mean performance on EC2 and Eucalyptus-based cloud systems. Our analysis eliminates variations in IO and computational times as possible causes, we find that variations in communication times account for the bulk of the experiment-to-experiment fluctuations of the performance.