With Exascale systems on the horizon, we will be ushering in an era with power
and energy consumption as a key concern for scalable computing. To achieve
viable high performance, a combination of evolutionary and revolutionary
methods is required with a stronger integration among hardware features, system
software and applications. Equally important are the capabilities for
fine-grained spatial and temporal measurement and control to facilitate energy
efficient computing across all layers. Current approaches for energy efficient
computing rely heavily on power efficient hardware in isolation. However, it is
pivotal for hardware to expose mechanisms for energy efficiency to optimize
power and energy consumption for various workloads and to reduce data motion,
a major component of energy use. At the same time, high fidelity measurement
techniques, typically ignored in data-center level measurement, are of high
importance for scalable and energy efficient inter-play at different layers of
application, system software and hardware.