Dynamic Traffic Regulation in NoC-Based Systems

In network-on-chip (NoC)-based systems, performance enhancement has primarily focused on the network itself, with little attention paid on controlling traffic injection at the network boundary. This is unsatisfactory because traffic may be over injected, aggravating congestion, and lowering performance. Recently, traffic regulation is proposed as an orthogonal means for performance improvement. Rather than as soon as possible admission, traffic regulation may hold back packet injection by admitting packets into the network only when the accumulated traffic volume at any time interval does not exceed a threshold. These regulation techniques are, however, often static, likely causing overregulation and underregulation. We propose dynamic traffic regulation to improve the system performance for NoC-based multi/many-processor systems-on-chip (MPSoC) and chip multi/many-core processor (CMP) designs. It can be applied to MPSoCs for intellectual property integration in an open-loop fashion by injecting traffic according to its run-time profiled characteristics. It can also be applied to CMPs in a closed-loop fashion by admitting traffic fully adaptive to the traffic and network states. Through extensive experiments and results, we show that both the open-loop and closed-loop dynamic regulation techniques can significantly improve the network and system performance.