The What's Next Intermittent Computing Architecture

Energy-harvesting devices operate under extremely tight energy constraints. Ensuring forward progress under frequent power outages is paramount. Applications running on these devices are typically amenable to approximation, offering new opportunities to provide better forward progress between power outages. We propose What's Next (WN), a set of anytime approximation techniques for energy harvesting: subword pipelining, subword vectorization and skim points. Skim points fundamentally decouple the checkpoint location from the recovery location upon a power outage. Ultimately, WN transforms processing on energy-harvesting devices from all-or-nothing to as-is computing. We enable an approximate (yet acceptable) result sooner and proceed to the next task when power is restored rather than resume processing from a checkpoint to yield the perfect output. WN yields speedups of 2.26x and 3.02x on non-volatile and checkpoint-based volatile processors, while still producing high-quality outputs.