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For 2D mesh based Network-on-Chip (NoC), the prohibited turns of routing algorithms should be repetitively distributed in order for the routing algorithms to be implemented by logic-based circuit. In this paper, we aim to exploit the designing space for logic-based routing algorithms, and propose new logic-based routing algorithms that outperform the state-of-the-art counterparts. Toward this direction, we firstly construct all routing algorithms for $5 \times 5$ 2D mesh topology. Then we select those routing algorithms which have repetitive prohibited turns across both the network rows and columns. In addition, we chose those routing algorithms that have smaller routing pressures than Odd-Even routing algorithm. Then the routing algorithms for 2D mesh topology ranging from $6 \times 6$ to $15 \times 15$ are respectively constructed according to the prohibited turns distribution of the selected routing algorithms. Two routing algorithms that have smaller routing pressures than Odd-Even routing algorithm are obtained for all considered networks. The obtained logic-based routing algorithms are called as Repetitive Turn Model (RTM). Simulation results show that RTM could achieve up to 51% performance improvement as compared to Odd-Even routing algorithm. [ABSTRACT FROM AUTHOR]

Network-on-Chip (NoC) has been made the communication infrastructure for many-core architecture. NoC are subject to congestion, which is claimed to be avoided by many researchers. However, there is no completely understanding of congestion in literature, which hinders its solution. Toward this direction, we firstly carry out study on congestion in this paper. We find that congestion usually occurs at a portion of nodes in a local network region. Moreover, local congestion will significantly decrease system performance and mostly impact some particular communication pairs. Then we attempt to solve local congestion by addressing different local region size, based on Divide-Conquer approach and routing pressure. It avoids congestion in every local region by keeping routing pressure of every local region minimum. Using different local region size will create different routings. Our study shows that the local region size is closely related with the routing performance. When local region size is 5 × 5 the optimal routing performance of large size network could be achieved. [ABSTRACT FROM AUTHOR]

How to precisely measure performance of routing algorithm is an important issue when studying routing algorithm of network-on-chip (NoC). The degree of adaptiveness is the most widely used metric in the literature. However, our study shows that the degree of adaptiveness cannot precisely measure performance of routing algorithm. It cannot account for why routing algorithm with high degree of adaptiveness may have poor performance. Simulation has to be carried out to evaluate performance of routing algorithm. In this paper, we propose a new metric of routing pressure for measuring performance of routing algorithm. It has higher precision of measuring routing algorithm performance than the degree of adaptiveness. Performance of routing algorithm can be evaluated through routing pressure without simulation. It can explain why congestion takes place in network. In addition, where and when congestion takes place can be pointed out without simulation. [ABSTRACT FROM AUTHOR]

As a scalable substitute of on-chip bus, network-on-chip (NoC) is proposed as the communication infrastructure in modern multi/many-core system-on-chip (SoC). Efficient communication in NoC is critical to the overall SoC performance. Although local congestion has an important impact on communication delay, it is barely taken into account when designing routing algorithms. In this paper, we propose an offline methodology of designing routing algorithm based on channel pressure model to address the local congestion issue. Specifically, the proposed methodology uses divide-conquer with the aim of generating high performance routing algorithms, which are able to balance the load over the network with a consequent reduction of local congestion. By using the proposed methodology, the obtained routing could achieve up to 37% performance improvement (in terms of average communication delay) as compared to the well-known odd-even routing algorithm for $15\times 15$ network. [ABSTRACT FROM PUBLISHER]