Lawrence Berkeley National Laboratory

The problem of ranking the utility of supercomputer systems arises frequently in situations such as procurements and other types of evaluations of architectures. It is also central for any general ranking of supercomputers such as the Top500. Rankings of computer systems have traditionally solely focused on performance aspects. In recent years restrictions due to power and space requirements of large supercomputers have become very noticeable, which has increased the importance of including these factors in generalized rankings. In this paper we present an overview of the current practice for utility metrics and analyze their shortcomings. We then present and discuss in detail a new concept for a parameterized utility metric for supercomputers, which is based on effective performance, available memory size, actual power consumption, and (if desired) the floor space required for supercomputers. This metric is designed and proposed for augmenting the current Top500 ranking.