Issue system protection mechanisms

Abstract

Multi-core microprocessors require reducing the FIT (failures-in-time) rate per core drastically to enable a larger number of cores within a FIT budget. Since large arrays like caches and register flies are typically protected with either ECC or parity, the issue system becomes as one of the largest contributors to the core's FIT rate. Soft-errors are an important concern in contemporary microprocessors. Particle hits on the components of a processor are expected to create an increasing number of transient errors in each new microprocessor generation. In addition, the number of hard-errors in the field is expected to grow as burn-in becomes less effective. Moreover, the continuous device shrinking increases the likelihood of in-the-field failures due to rather small defects exacerbated by degradation. This paper proposes on-line mechanisms to detect and recover to a consistent state, classify and confine in-the-field errors in the issue system of both in-order and out-of-order cores. Such mechanisms provide high coverage at a small cost.