Understanding ultra-scale application communication requirements

As thermal constraints reduce the pace of CPU performance improvements, the cost and scalability of future HPC architectures are increasingly dominated by the interconnect. In this paper we perform an in-depth study of the communication requirements across a broad spectrum of important scientific applications, whose computational methods include: finite-difference, lattice-Bolzmann, particle in cell, sparse linear algebra, particle mesh ewald, and FFT-based solvers. We use the IPM (integrated performance monitoring) profiling framework to collect detailed statistics on communication topology and message volume with minimal impact to code performance. By characterizing the parallelism and communication requirements of such a diverse set of applications, we hope to guide architectural choices for the design and implementation of interconnects for future HPC systems.