Fairness-oriented switch allocation for networks-on-chip

Networks-on-Chip (NoC) is becoming the backbone of modern chip multiprocessor (CMP) systems. However, with the number of integrated cores increasing and the network size scaling up, the network-latency imbalance is becoming an important problem, which seriously influences the performance of the network and system. In this paper, we aim to alleviate this problem by optimizing the design of switch allocation. We propose fairness-oriented switch allocation (FOSA), a novel switch allocation strategy to achieve uniform network latencies. FOSA can improve system performance by achieving remarkable improvement in balancing network latencies. We evaluate the network and system performance of FOSA with synthetic traffics and SPEC CPU2006 benchmarks in a full-system simulator. Compared with the canonical separable switch allocator (Round-Robin) and the recently proposed switch allocator (TS-Router), the experiments with benchmarks show that our approach decreases maximum latency (ML) by 45.6% and 15.1%, respectively, as well as latency standard deviation (LSD) by 13.8% and 3.9%, respectively. Besides this, FOSA improves system throughput by 0.8% over that of TS-Router. Finally, we synthesize FOSA and give an evaluation of the additional consumption of area and power.