UnSync-CMP: Multicore CMP architecture for energy-efficient soft-error reliability

Reducing device dimensions, increasing transistor densities, and smaller timing windows, expose the vulnerability of processors to soft errors induced by charge carrying particles. Since these factors are only consequences of the inevitable advancement in processor technology, the industry has been forced to improve reliability on general purpose chip multiprocessors (CMPs). With the availability of increased hardware resources, redundancy-based techniques are the most promising methods to eradicate soft-error failures in CMP systems. In this work, we propose a novel customizable and redundant CMP architecture (UnSync) that utilizes hardware-based detection mechanisms (most of which are readily available in the processor), to reduce overheads during error-free executions. In the presence of errors (which are infrequent), the always forward execution enabled recovery mechanism provides for resilience in the system. The inherent nature of our architecture framework supports customization of the redundancy, and thereby provides means to achieve possible performance-reliability tradeoffs in many-core systems. We provide a redundancy-based soft-error resilient CMP architecture for both write-through and write-back cache configurations. We design a detailed RTL model of our UnSync architecture and perform hardware synthesis to compare the hardware (power/area) overheads incurred. We compare the same with those of the Reunion technique, a state-of-the-art redundant multicore architecture. We also perform cycle-accurate simulations over a wide range of SPEC2000, and MiBench benchmarks to evaluate the performance efficiency achieved over that of the Reunion architecture. Experimental results show that, our UnSync architecture reduces power consumption by 34.5 percent and improves performance by up to 20 percent with 13.3 percent less area overhead, when compared to the Reunion architecture for the same level of reliability achieved.