Hot sparing for lifetime-chip-performance and cost improvement in application specific SIMT processors

Abstract

Redundancy is a well-known technique for replacing components with manufacturing defects, improving yield and reducing cost. Previously, most yield improvement strategies utilized redundant components only when another component had failed (i.e., cold spares). However, utilizing hot spares is becoming popular in commercial products (e.g., the NVIDIA Ti GPU series). Hot spares address manufacturing cost when the components are defective; otherwise, they can be used to improve performance in the field. In this paper, we investigate the effect of hot spares on lifetime-chip-performance (LCP) in multi-core single-instruction, multiple-thread (SIMT) processors. We observe that hot sparing is outstandingly effective for specific types of SIMT processor configurations (small and medium systems) and applications (FFT and FILTER), while improving cost and LCP over other configurations and applications as well. For example, hot-sparing can improve LCP more than 75% compared with conventional methods (i.e., cold sparing), on average, for applications that experience significant performance improvement when adding hot spares (e.g., FFT and FILTER). In particular, microarchitectural hot redundant resources (e.g., hot spare lanes) achieve better LCP improvement than conventional architectural redundancies (e.g., hot spare cores).