Programmable stochastic computing: Embracing errors in architecture and design of processors and applications

Abstract

All of computing today relies on an abstraction where software expects hardware to behave flawlessly for all inputs, under all conditions. While this abstraction worked well historically, due to the relatively small magnitude of variations in hardware and environment, computing will increasingly be done with devices and circuits that are inherently stochastic because of how small they are, or whose behavior is stochastic due to manufacturing and environmental uncertainties. For such emerging circuits and devices, the cost of guaranteeing correctness through guardbanding will be prohibitive, and we may need to rethink the correctness specification hardware needs to meet. Such rethinking may become particularly compelling considering that a significant amount of power is wasted in guaranteeing reliability even for applications that are inherently error tolerant.