Exploiting Approximate Computing to Increase System Lifetime

International audienceApproximate Computing (AxC) is today one of the hottest topics related to circuit design and optimization. Thanks to this new computing paradigm, designers are able to reduce area, power consumption, and even production costs in the case the target application can accept a given degree of inaccuracy in the final computations. This paper investigates the impact of accepting a faulty circuit as an approximate one in order to increase the system reliability. In particular, it considers two AxC techniques: functional approximation and precision reduction. The main goal of the paper is to determine the trade-off between the degree of the approximation and the reliability to give the system an additional chance to continue working, even if it does not work exactly as originally designed. The experimental results were gathered resorting to a set of 8-bit adders that includes some precise ones used in commercial applications, as well as some approximate ones. Additionally, the actual effects of the faulty circuits were evaluated at the application level: a video encoding system called NOVA was used, assessing the validity of the proposal