Blade -- A Timing Violation Resilient Asynchronous Template

Abstract

Resilient designs offer the promise to remove increasingly large margins due to process, voltage, and temperature variations and take advantage of average-case data. However, proposed synchronous resilient schemes have either suffered from metastability or require modifying the architecture to add replay-based logic that recovers from timing errors, which leads to high timing error penalties and poses a design challenge in modern processors. This paper presents an asynchronous bundled-data resilient template called Blade that is robust to metastability issues, requires no replay-based logic, and has low timing error penalties. The template is supported by an automated design flow that synthesizes synchronous RTL designs to gate-level asynchronous Blade designs. The benefits of this flow are illustrated on Plasma, a 3-stage Open Core MIPS CPU. Our results demonstrate that a nominal area overhead of the asynchronous template of less than 10% leads to a 19% performance boost over the synchronous design due to average-case data and a 30-40% improvement when synchronous PVT margins are considered.