Understanding Power Measurement Implications in the Green500 List

For decades, performance has been the driving force behind high-performance computing (HPC). However, in recent years, power consumption has become an important constraint as operational costs of a supercomputer are now on par with the acquisition costs of a supercomputer. Even though we face major energy issues in achieving large-scale performance, there is still a lack of a standardized power measurement methodology in the HPC community for energy-efficient supercomputing. In this paper, we report on our experiences in updating the run rules for The Green500 List with a particular emphasis on the power measurement methodology. We use high-performance LINPACK (HPL) to study power measurement techniques that can be applied for large-scale HPC systems. We formulate experiments to provide insight into the power measurement issues in large-scale systems with the goal of improving the readers' understanding of the measurement methodology for the Green500 list.