System-Level Effects of Soft Errors in Uncore Components

Abstract

The effects of soft errors in processor cores have been widely studied. However, little has been published about soft errors in uncore components, such as the memory subsystem and I/O controllers, of a system-on-a-chip (SoC). In this paper, we study how soft errors in uncore components affect system-level behaviors. We have created a new mixed-mode simulation platform that combines simulators at two different levels of abstraction, and achieves $20~000{\times }$ speedup over register-transfer-level-only simulation. Using this platform, we present the first study of the system-level impact of soft errors inside various uncore components of a large-scale, multicore SoC using the industrial-grade, open-source OpenSPARC T2 SoC design. Our results show that soft errors in uncore components can significantly impact system-level reliability. We also demonstrate that uncore soft errors can create major challenges for traditional system-level checkpoint recovery techniques. To overcome such recovery challenges, we present a new replay recovery technique for uncore components belonging to the memory subsystem. For the L2 cache controller and the dynamic random-access memory controller components of OpenSPARC T2, our new technique reduces the probability that an application run fails to produce correct results due to soft errors by more than $50 {\times }$ with 1.82% and 2.58% chip-level area and power impact, respectively.