The Power-Optimised Software Envelope

Advances in processor design have delivered performance improvements for decades. As physical limits are reached, refinements to the same basic technologies are beginning to yield diminishing returns. Unsustainable increases in energy consumption are forcing hardware manufacturers to prioritise energy efficiency in their designs. Research suggests that software modifications may be needed to exploit the resulting improvements in current and future hardware. New tools are required to capitalise on this new class of optimisation. In this paper, we present the Power Optimised Software Envelope (POSE) model, which allows developers to assess the potential benefits of power optimisation for their applications. The POSE model is metric agnostic and in this paper we provide derivations using the established Energy-Delay Product metric and the novel Energy-Delay Sum and Energy-Delay Distance metrics that we believe are more appropriate for energy-aware optimisation efforts. We demonstrate POSE on three platforms by studying the optimisation characteristics of applications from the Mantevo benchmark suite. Our results show that the Pathfinder application has very little scope for power optimisation while TeaLeaf has the most, with all other applications in the benchmark suite falling between the two. Finally, we extend our POSE model with a formulation known as System Summary POSE – a meta-heuristic that allows developers to assess the scope a system has for energy-aware software optimisation independent of the code being run.