Tactics for Software Energy Efficiency: A Review

Over the years, software systems experienced a growing popularization. With it, the energy they consume witnessed an exponential growth, surpassing the one of the entire aviation sector. Energy efficiency tactics can be used to optimize software energy consumption. In this work, we aim at understanding the state of the art of energy efficient tactics, in terms of activities in the field, tactic properties, tactic evaluation rigor, and potential for industrial adoption. We leverage a systematic literature review based on a search query and two rounds of bi-directional snowballing. We identify 142 primary studies, reporting on 163 tactics, which we extract and analyze via a mix of qualitative and quantitative research methods. The research interest in the topic peaked in 2015 and then steadily declined. Tactics on source code static optimizations and application level dynamic monitoring are the most frequently studied. Industry involvement is limited. This potentially creates a vicious cycle in which practitioners cannot apply tactics due to low industrial relevance, and academic researchers struggle to increase the industrial relevance of their findings. Despite the energy consumed by software is a growing concern, the future of energy efficiency tactics research does not look bright. From our results emerges a call for action, the need for academic researchers and industrial practitioners to join forces for creating real impact.