Quasi-Static Voltage Scaling for Energy Minimization With Time Constraints

Supply voltage scaling and adaptive body biasing (ABB) are important techniques that help to reduce the energy dissipation of embedded systems. This is achieved by dynamically adjusting the voltage and performance settings according to the application needs. In order to take full advantage of slack that arises from variations in the execution time, it is important to recalculate the voltage (performance) settings during runtime, i.e., online. However, optimal voltage scaling algorithms are computationally expensive, and thus, if used online, significantly hamper the possible energy savings. To overcome the online complexity, we propose a quasi-static voltage scaling (QSVS) scheme, with a constant online time complexity O(1). This allows to increase the exploitable slack as well as to avoid the energy dissipated due to online recalculation of the voltage settings.