ExtraTime: Modeling and analysis of wearout due to transistor aging at microarchitecture-level

With shrinking feature sizes, transistor aging due to NBTI and HCI becomes a major reliability challenge for microprocessors. These processes lead to increased gate delays, more failures during runtime and eventually reduced operational lifetime. Currently, to ensure correct functionality for a certain operational lifetime, additional timing margins are added to the design. However, this approach implies a significant performance loss and may fail to meet reliability requirements. Therefore, aging-aware microarchitecture design is inevitable. In this paper we present ExtraTime, a novel microarchitectural aging analysis framework, which can be used in early design phases when detailed transistor-level information is not yet available to model, analyze, and predict performance, power and aging. Furthermore, we show a comprehensive investigation using ExtraTime of various clock and power gating strategies as well as aging-aware instruction scheduling policies as a case study to show the impact of the architecture on aging.