Load-Balanced Link Distribution in Mesh-Based Many-Core Systems

Networks-on-Chip (NoC) is becoming the fundamental infrastructure of modern chip multiprocessors (CMPs). Along with the scaling up for a mesh-based network, the inequivalence of location for the links gradually causes unbalanced traffic load on each link. In a mesh network, the central regions are easy to become the hotspots, and the central links are heavily utilized than the peripheral links in the context of non-uniform cache architecture (NUCA). Different from the traditional uniform interconnection between network nodes, we propose the load-balanced link distribution scheme, which aims at assigning physical channels in accordance with the traffic load of each link. In this paper, we analyze the traffic load distribution for the mesh network with different scales and give the corresponding load-balanced link distributions. The simulation results indicate that the load-balanced scheme achieves not only lower physical channel costs but also better network and system performance than the traditional uniform scheme. The experiments with synthetic traffics show that the load-balanced scheme exhibits 57.33%/60.23%/47.56% lower network latency at saturation point on average compared with the uniform scheme for 8x8/10x10/12x12 mesh networks respectively. By contrast, the load-balanced link distribution scheme uses less physical channels, and the reductions in physical channel cost are 7.14%/5.56%/15.15% for 8x8/10x10/12x12 mesh networks respectively. The experiments with PARSEC benchmarks reveal that a 2.1% improvement of system throughput can be achieved by the load-balanced scheme.