Performance comparison of scientific applications on Cray architectures

Current HPC architectures are changing drastically and rapidly as compared to mature scientific applications, which usually evolve at a much slower rate. Newly introduced architectures promise to impact the performance of these heavily used scientific applications. Therefore, it is prudent to understand how the supposed performance benefits and improvements of new architectures translate to the applications. In this paper, we attempt to quantify the differences between the theoretical performance improvements (due to changes in architecture) and the “real-world” improvements in applications by gathering performance data of selected applications from the fields of chemistry, climate, weather, materials science, fusion, and astrophysics running on three different Cray architectures: XT5, XE6, and XC30. Of particular interest is the fact that these three Cray platforms spans three different generations of interconnects, namely: SeaStar2+, Gemini, and Aries, respectively and that all three platforms (or its variant) are either in active use or coming online at HPC centers. Therefore, a performance evaluation of these selected applications on these three different architectures gives a user some useful perspective into the benefits of these architectures. These evaluations are done by comparing the improvements of numerical (micro)-benchmarks to the improvements of the selected applications when run across these architectures. Keywords-Performance; Benchmarking; Computer architecture