A New Methodology for Reduced Cost of Resilience

Abstract

Resilient design techniques are used to (i) ensure correct operation under dynamic variations; and (ii) improve design performance (e.g., through timing speculation). However, significant overheads (e.g., 17% and 15% energy penalties due to throughput degradation and additional circuits) are incurred by existing resilient design techniques. For instance, resilient designs require additional circuits to detect and correct timing errors. Further, when there is an error, the additional cycles needed to restore a previous correct state degrade throughput, which diminishes the performance benefit of using resilient designs. In this work, we propose a methodology for resilient design implementation to minimize the costs of resilience in terms of power, area and throughput degradation. Our methodology uses two levers: selective-endpoint optimization (i.e., sensitivity-based margin insertion) and clock skew optimization. We integrate the two optimization techniques in an iterative optimization flow which comprehends toggle rate information and the tradeoff between cost of resilience and margin on combinational paths. Our proposed flow achieves energy reductions of up to 19% and 21% compared to a conventional design (with only margin used to attain robustness) and a brute-force implementation, respectively. These benefits increase in the context of an adaptive voltage scaling strategy.