Enabling intermittent computing on high-performance out-of-order processors

Intermittent computing is a new paradigm enabling battery-less computing devices to be powered directly from energy harvesting, enabling IoT devices that are free from the cost, size and lifetime constraints of batteries. To cope with frequent power interruptions, intermittent computing systems save computational progress before power is lost, and restore it when power returns. Recent research in power-neutral operation of multiprocessor system-on-chips (MPSoCs), where performance scaling is used to instantaneously match power consumption with supply, motivates the need for intermittent computing on high-performance systems. Existing works provide solutions for microcontrollers, but with the increased complexity of high-performance SoCs, new challenges such as hierarchical memory and dependence on large existing libraries emerge. In this paper, we provide a taxonomy of published intermittent computing methods and identify the most suitable method for high-performance SoCs. The chosen method is then implemented and experimentally validated on an Arm A9 out-of-order application processor. Results show that state can be saved/restored correctly in 8.6 ms for a minimal bare-metal application, which is an order of magnitude faster than the platform's hardware boot time.