Emerging Trends on the Evolving Green500: Year Three

It has been traditionally viewed that as the scale of a supercomputer increases, its energy efficiency decreases due to performance that scales sub-linearly and power consumption that scales at least linearly with size. However, based on the first three years of the Green500, this view does not hold true for the fastest supercomputers in the world. Many reasons for this counterintuitive trend have been proposed - with improvements in feature size, more efficient networks, and larger numbers of slower cores being amongst the most prevalent. Consequently, this paper provides an analysis of emerging trends in the Green500 and delves more deeply into how larger-scale supercomputers compete with smaller-scale supercomputers with respect to energy efficiency. In addition, our analysis provides a compelling early indicator of the future of exascale computing. We then close with a discussion on the evolution of the Green500 based on community feedback.