TIMBER: Time borrowing and error relaying for online timing error resilience

Abstract

Increasing dynamic variability with technology scaling has made it essential to incorporate large design-time timing margins to ensure yield and reliable operation. Online techniques for timing error resilience help recover timing margins, improving performance and/or power consumption. This paper presents TIMBER, a technique for online timing error resilience that masks timing errors by borrowing time from successive pipeline stages. TIMBER-based error masking can recover timing margins without instruction replay or roll-back support. Two sequential circuit elements --- TIMBER flip-flop and TIMBER latch --- that implement error masking based on time-borrowing are described. Both circuit elements are validated using corner-case circuit simulations, and the overhead and trade-offs of TIMBER-based error masking are evaluated on an industrial processor.