  Energy efficiency is of paramount importance for the sustainability of HPC
systems. Energy consumption limits the peak performance of supercomputers and
accounts for a large share of total cost of ownership. Consequently, system
owners and final users have started exploring mechanisms to trade off
performance for power consumption, for example through frequency and voltage
scaling.
  However, only a limited number of studies have been devoted to explore the
economic viability of performance scaling solutions and to devise pricing
mechanisms fostering a more energy-conscious usage of resources, without
adversely impacting return-of-investment on the HPC facility. We present a
parametrized model to analyze the impact of frequency scaling on energy and to
assess the potential total cost benefits for the HPC facility and the user. We
evaluate four pricing schemes, considering both facility manager and the user
perspectives. We then perform a design space exploration considering current
and near-future HPC systems and technologies.
