High-performance, Energy-efficient, Fault-tolerant Network-on-Chip Design Using Reinforcement Learnin

Network-on-Chips (NoCs) are becoming the standard communication fabric for multi-core and system on a chip (SoC) architectures. As technology continues to scale, transistors and wires on the chip are becoming increasingly vulnerable to various fault mechanisms, especially timing errors, resulting in exacerbation of energy efficiency and performance for NoCs. Typical techniques for handling timing errors are reactive in nature, responding to the faults after their occurrence. They rely on error detection/correction techniques which have resulted in excessive power consumption and degraded performance, since the error detection/correction hardware is constantly enabled. On the other hand, indiscriminately disabling error handling hardware can induce more errors and intrusive retransmission traffic. Therefore, the challenge is to balance the trade-offs among error rate, packet retransmission, performance, and energy. In this paper, we propose a proactive fault-tolerant mechanism to optimize energy efficiency and performance with reinforcement learning (RL). First, we propose a new proactive error handling technique comprised of a dynamic scheme for enabling per-router error detection/correction hardware and an effective retransmission mechanism. Second, we propose the use of RL to train the dynamic control policy with the goals of providing increased fault-tolerance, reduced power consumption and improved performance as compared to conventional techniques. Our evaluation indicates that, on average, end-to-end packet latency is lowered by 55%, energy efficiency is improved by 64%, and retransmission caused by faults is reduced by 48% over the reactive error correction techniques.