Parity-based mono-Copy Cache for low power consumption and high reliability

The power consumption is one of the most important preoccupations of the chip designers. However, reducing power consumption has its negative impact on the circuit. For example, reducing the supply voltage of a microprocessor implies an increase in the probability of process-variation-induced failures. Fault tolerant architectures propose a trade-off by boosting the reliability while reducing power consumption. Since a large part of the microprocessor power is consumed by the cache memory, we propose in this paper the Parity-based mono-Copy Cache (PmC²) that maintains cache reliability under aggressive voltage scaling. PmC² results in reducing energy consumption considerably with very low performance penalty. PmC² uses a parity check mechanism in error detection and only one cache block redundancy for error correction. Our experimental results demonstrate that reducing the supply voltage with roughly 25% of nominal Vdd achieves more than 62% reduction in cache power consumption with a negligible IPC loss that does not exceed 0.15%.