Preparing for exascale: modeling MPI for many-core systems using fine-grain queues

This paper presents a fine-grain queueing model of MPI point-to-point messaging performance for use in the design and analysis of current and future large-scale computing systems. In particular, the model seeks to capture key performance behavior of MPI communication on many-core systems. We demonstrate that this model encompasses key MPI performance characteristics, such as short/long protocol and offload/onload protocol tradeoffs, and demonstrate its use in predicting the potential impact of architectural and software changes for many-core systems on communication performance. In addition, we also discuss the limitations of this model and potential directions for enhancing its fidelity.