Electromigration-Aware Memory Hierarchy Architecture

New mission-critical applications, such as autonomous vehicles and life-support systems, set a high bar for the reliability of modern microprocessors that operate in highly challenging conditions. However, while cutting-edge integrated circuit (IC) technologies have intensified microprocessors by providing remarkable reductions in the silicon area and power consumption, they also introduce new reliability challenges through the complex design rules they impose, creating a significant hurdle in the design process. In this paper, we focus on electromigration (EM), which is a crucial factor impacting IC reliability. EM refers to the degradation process of IC metal nets when used for both power supply and interconnecting signals. Typically, EM concerns have been addressed at the backend, circuit, and layout levels, where EM rules are enforced assuming extreme conditions to identify and resolve violations. This study presents new techniques that leverage architectural features to mitigate the effect of EM on the memory hierarchy of modern microprocessors. Architectural approaches can reduce the complexity of solving EM-related violations, and they can also complement and enhance common existing methods. In this study, we present a comprehensive simulation analysis that demonstrates how the proposed solution can significantly extend the lifetime of a microprocessor’s memory hierarchy with minimal overhead in terms of performance, power, and area while relaxing EM design efforts.