Reliable data path design of VLIW processor cores with comprehensive error-coverage assessment

In this paper, an effective fault-tolerant framework offering very high error coverage with zero detection latency is proposed to protect the data paths of VLIW processor cores. The feature of zero detection latency is essential to real-time error-recovery. The proposed framework provides the error-handling schemes of varying hardware complexity, performance and error coverage to be selected. A case study with an experimental VLIW architecture implemented in VHDL was used to demonstrate the impacts of our technique on hardware overhead and performance degradation. The fault injection experiments were performed to characterize the effects of fault-occurring frequency as well as workload variations on the error coverage, and the permanent faults on the length of time spent for error-recovery. The results observed from the experiments show that our approach can well protect the VLIW data paths even in a very severe fault scenario. As a result, the proposed fault-tolerant VLIW core is quite suitable for the highly dependable embedded applications.