Update rate tradeoffs for improving online power modeling in smartphones

Smartphones offer sophisticated features (e.g., Wi-Fi, GPS, etc.) that require significant energy and limit battery life. Offline smartphone power modeling with benchtop equipment is cumbersome for software developers and takes substantial time to perform on multiple devices. By running on the device itself, online modeling can be performed dynamically and is scalable to many different smartphones. Previous online modeling work used existing battery management unit (BMU) current sensors with a high internal sample rate (18.6 kHz), but very low (software-readable) output register update rates (0.28 Hz). We propose allowing the register update rate to be dynamically adjusted to decrease online modeling time and energy cost. In this work we consider the benefits and evaluate the trade-offs of this approach.