Aging-Resilient Topology Synthesis of Heterogeneous Manycore Network-On-Chip Using Genetic Algorithm with Flexible Number of Routers

Abstract

As semiconductor processes enter the nanoscale, system-on-chip (SoC) interconnects suffer from link aging owing to negative bias temperature instability (NBTI), hot carrier injection (HCI), and electromigration. In network-on-chip (NoC) for heterogeneous manycore systems, there is a difference in the aging speed of links depending on the location and utilization of resources. In this paper, we propose a heterogeneous manycore NoC topology synthesis that predicts the aging effect of each link and deploys routers and error correction code (ECC) logic. Aging-aware ECC logic is added to each link to achieve the same link lifetime with less area and latency than the Bose-Chaudhuri-Hocquenghem (BCH) logic. Moreover, based on the modified genetic algorithm, we search for a solution that minimizes the average latency while ensuring the link lifetime by changing the number of routers, location, and network connectivity. Simulation results demonstrate that the aging-aware topology synthesis reduces the average latency of the network by up to 26.68% compared with the aging analysis and the addition of ECC logic on the link after the topology synthesis. Furthermore, topology synthesis with aging-aware ECC logic reduces the maximum average latency by up to 39.49% compared with added BCH logic.improve NoC performance in heterogeneous manycore NoC designs. Existing schemes have applied a fixed number of routers in the chip. These methods make it possible to find a reasonable solution in NoC with a specific number of routers. However, in situations where the number of routers is not assigned, algorithms must be executed several times for different numbers of routers, which requires additional computation time.In contrast, due to the miniaturization of semiconductor processes, delay faults in communication data due to the aging of flip-flops and metal wires have become a significant concern in the SoC interconnect design [8][9][10]. In the nanoscale process, aging-induced delay faults occur mainly due to negative bias temperature instability (NBTI), hot carrier injection (HCI), and electromigration [11][12][13][14][15]. NBTI and HCI increase the threshold voltage of the transistors, and electromigration increases the resistance in metal wires, resulting in longer data transfer delay [8,9,15].Few studies have considered the aging effect in the high-level design of the on-chip interconnect, because it was treated as a low-level design problem. However, recent studies show that in the topology synthesis of heterogeneous manycore NoC, the aging process can be predicted based on the length and communication load of each link [14][15][16]. If the aging effect of each link is taken into consideration during the NoC topology synthesis, it is possible to reduce the performance degradation through the placement of interconnect modules and links. Moreover, this will aid in the recovery of aging resilience by correcting the error even if a delay fault occurs by using the error correction logic.The forward error correction, based on error cor...

Q-Function-Based Traffic- and Thermal-Aware Adaptive Routing for 3D Network-on-Chip

“…However, the ever-increasing traffic between the processing elements created bottlenecks in conventional bus-based CMPs [2]. Initially, a 2D network-on-chip (NoC) was proposed for mitigating the complexities in the on-chip interconnection network [3]. Although a 2D NoC has the advantages of high scalability and simple fabrication structure, high performance is not guaranteed, owing to the rapid deterioration in packet latency associated with increasing physical distances as the number of processing cores increases [4].…”