Complex version of high performance computing LINPACK benchmark (HPL)

This paper describes our effort to enhance the performance of the AORSA fusion energy simulation program through the use of High Performance LINPACK (HPL) benchmark, commonly used in ranking the top 500 supercomputers. The algorithm used by HPL, enhanced by a set of tuning options, is more effective than that found in the ScaLAPACK library. Retrofitting these algorithms, such as look-ahead processing of pivot elements, into ScaLAPACK is considered a major undertaking. Moreover, HPL is configured as a benchmark, and only for real-valued coefficients. We therefore developed software to convert HPL for use within an application program that generates complex coefficient linear systems. Although HPL is not normally perceived as part of an application, our results show the modified HPL software brings a significant increase in performance of the solver when simulating the highest resolution experiments thus far configured, achieving 87.5 TFLOPS on over 20,000 processors on the Cray XT4.