Asymmetric Aging Effect on Modern Microprocessors

Abstract: Reliability is a crucial requirement in any modern microprocessor to assure correct execution over its lifetime. As mission critical components are becoming common in commodity systems; e.g., control of autonomous cars, the demand for reliable processing has even further heightened. Latest process technologies even worsened the situation; thus, microprocessors design has become highly susceptible to reliability concerns. This paper examines asymmetric aging phenomenon, which is a major reliability concern in advanced process nodes. In this phenomenon, logical elements and memory cells suffer from unequal timing degradation over time and consequently introduce reliability concerns. So far, most studies approached asymmetric aging from circuit or physical design viewpoint, but these solutions were quite limited and suboptimal. In this paper we introduce an asymmetric aging aware micro-architecture that aims at reducing its impact. The study is mainly focused on the following subsystems: execution units, register files and the memory hierarchy. Our experiments indicate that the proposed solutions incur minimal overhead while significantly mitigating the asymmetric aging stress.