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

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 392 ◽  
Author(s):  
Seung Chan Lee ◽  
Tae Hee Han

Die-stacking technology is expanding the space diversity of on-chip communications by leveraging through-silicon-via (TSV) integration and wafer bonding. The 3D network-on-chip (NoC), a combination of die-stacking technology and systematic on-chip communication infrastructure, suffers from increased thermal density and unbalanced heat dissipation across multi-stacked layers, significantly affecting chip performance and reliability. Recent studies have focused on runtime thermal management (RTM) techniques for improving the heat distribution balance, but performance degradations, owing to RTM mechanisms and unbalanced inter-layer traffic distributions, remain unresolved. In this study, we present a Q-function-based traffic- and thermal-aware adaptive routing algorithm, utilizing a reinforcement machine learning technique that gradually incorporates updated information into an RTM-based 3D NoC routing path. The proposed algorithm initially collects deadlock-free directions, based on the RTM and topology information. Subsequently, Q-learning-based decision making (through the learning of regional traffic information) is deployed for performance improvement with more balanced inter-layer traffic. The simulation results show that the proposed routing algorithm can improve throughput by 14.0%–28.2%, with a 24.9% more balanced inter-layer traffic load and a 30.6% more distributed inter-layer thermal dissipation on average, compared with those obtained in previous studies of a 3D NoC with an 8 × 8 × 4 mesh topology.

2011 ◽  
Vol 474-476 ◽  
pp. 413-416
Author(s):  
Jia Jia ◽  
Duan Zhou ◽  
Jian Xian Zhang

In this paper, we propose a novel adaptive routing algorithm to solve the communication congestion problem for Network-on-Chip (NoC). The strategy competing for output ports in both X and Y directions is employed to utilize the output ports of the router sufficiently, and to reduce the transmission latency and improve the throughput. Experimental results show that the proposed algorithm is very effective in relieving the communication congestion, and a reduction in average latency by 45.7% and an improvement in throughput by 44.4% are achieved compared with the deterministic XY routing algorithm and the simple XY adaptive routing algorithm.


2021 ◽  
Vol 20 (3) ◽  
pp. 1-6
Author(s):  
Mohammed Shaba Saliu ◽  
Muyideen Omuya Momoh ◽  
Pascal Uchenna Chinedu ◽  
Wilson Nwankwo ◽  
Aliu Daniel

Network-on-Chip (NoC) has been proposed as a viable solution to the communication challenges on System-on-Chips (SoCs). As the communication paradigm of SoC, NoCs performance depends mainly on the type of routing algorithm chosen. In this paper different categories of routing algorithms were compared. These include XY routing, OE turn model adaptive routing, DyAD routing and Age-Aware adaptive routing.  By varying the load at different Packet Injection Rate (PIR) under random traffic pattern, comparison was conducted using a 4 × 4 mesh topology. The Noxim simulator, a cycle accurate systemC based simulator was employed. The packets were modeled as a Poisson distribution; first-in-first-out (FIFO) input buffer channel with a depth of five (5) flits and a flit size of 32 bits; and a packet size of 3 flits respectively. The simulation time was 10,000 cycles. The findings showed that the XY routing algorithm performed better when the PIR is low.  In a similar vein, the DyAD routing and Age-aware algorithms performed better when the load i.e. PIR is high.


Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1076 ◽  
Author(s):  
Zulqar Nain ◽  
Rashid Ali ◽  
Sheraz Anjum ◽  
Muhammad Khalil Afzal ◽  
Sung Won Kim

Scalability is a significant issue in system-on-a-chip architectures because of the rapid increase in numerous on-chip resources. Moreover, hybrid processing elements demand diverse communication requirements, which system-on-a-chip architectures are unable to handle gracefully. Network-on-a-chip architectures have been proposed to address the scalability, contention, reusability, and congestion-related problems of current system-on-a-chip architectures. The reliability appears to be a challenging aspect of network-on-a-chip architectures because of the physical faults introduced in post-manufacturing processes. Therefore, to overcome such failures in network-on-a-chip architectures, fault-tolerant routing is critical. In this article, a network adaptive fault-tolerant routing algorithm is proposed, where the proposed algorithm enhances an efficient dynamic and adaptive routing algorithm. The proposed algorithm avoids livelocks because of its ability to select an alternate outport. It also manages to bypass congested regions of the network and balances the traffic load between outports that have an equal number of hop counts to its destination. Simulation results verified that in a fault-free scenario, the proposed solution outperformed a fault-tolerant XY by achieving a lower latency. At the same time, it attained a higher flit delivery ratio compared to the efficient dynamic and adaptive routing algorithm. Meanwhile, in the situation of a faulty network, the proposed algorithm could reach a higher flit delivery ratio of up to 18% while still consuming less power compared to the efficient dynamic and adaptive routing algorithm.


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