Automatic identification and hardware implementation of a resource-constrained power model for embedded systems

In modern embedded systems, the use of hardware-level online power monitors is crucial to support the run-time power optimizations required to meet the ever increasing demand for energy efficiency. To be effective and to deal with the time-to-market pressure, the presence of such requirements must be considered even during the design of the power monitoring infrastructure. This paper presents a power model identification and implementation strategy with two main advantages over the state-of-the-art. First, our solution trades the accuracy of the power model with the amount of resources allocated to the power monitoring infrastructure. Second, the use of an automatic power model instrumentation strategy ensures a timely implementation of the power monitor regardless the complexity of the target computing platforms. Our methodology has been validated against 8 accelerators generated through a High-Level-Synthesis flow and by considering a more complex RISC-V embedded computing platform. Depending on the imposed user-defined constraints and with respect to the unconstrained power monitoring state-of-the-art solutions, our methodology shows a resource saving between 37.3% and 81% while the maximum average accuracy loss stays within 5%, i.e., using the aggressive 20us temporal resolution. However, by varying the temporal resolution closer to the value proposed in the state of the art, i.e. in the range of hundreds of microseconds, the average accuracy loss of our power monitors is lower than 1% with almost the same overheads. In addition, our solution demonstrated the possibility of delivering a resource constrained power monitor employing a 20us temporal resolution, i.e., far higher the one used by current state-of-the-art solutions.