Speed scaling: an algorithmic perspective

Speed scaling has long been used as a power-saving mechanism at a chip level. However, in recent years, speed scaling has begun to be used as an approach for trading off energy usage and performance throughout all levels of computer systems. This wide-spread use of speed scaling has motivated significant research on the topic, but many fundamental questions about speed scaling are only beginning to be understood. In this chapter, we focus on a simple, but general, model of speed scaling and provide an algorithmic perspective on four fundamental questions: (i) What is the structure of the optimal speed scaling algorithm? (ii) How does speed scaling interact with scheduling? (iii) What is the impact of the sophistication of speed scaling algorithms? and (iv) Does speed scaling have any unintended consequences? For each question we provide a summary of insights from recent work on the topic in both worst-case and stochastic analysis as well as a discussion of interesting open questions that remain.