SAVS: a self-adaptive variable supply-voltage technique for process-tolerant and power-efficient multi-issue superscalar processor design

Technology scaling and sub-wavelength optical lithography is associated with significant process variations. We propose a self-adaptive variable supply-voltage scaling (SAVS) technique for multi-issue out-of-order pipeline to improve parametric yield with minimal power dissipation. Our error-correction circuitry and recovery mechanism allow the proposed fault-tolerant pipeline to work at a dynamically tuned supply voltage with a very low error rate. Experiments on an 8-issue, out-of-order superscalar processor show that SAVS can achieve 93.3% yield with 8.66% total power reduction under a scaled Vdd, compared to the same yield achieved by conventional microarchitecture. The increased execution time is negligible (0.014%).