Research On Large-Capacity 3D Optical Network-on-Chip For Many Cores

With the increase of the number of IP(Intellecture Property)cores on the chip,the interconnection problem between IP cores becomes the main bottleneck restricting the performance improvement of the chip.The efficient interconnection between a large number of IP cores becomes an urgent problem to be solved.ONo C(Optical Network-on-Chip)attracts a lot of attention from scholars at home and abroad because of its great advantages in communication speed,bandwidth,power consumption,crosstalk,scalability and design reusability.However,it is difficult for the traditional ONo C communication architecture to meet the severe requirements imposed by the large-scale chip of many cores and even thousands of cores on the integration degree and communication capacity of the system.Under this background,with the goal of improving the network capacity of the on-chip interconnect system,focusing on the three-dimensional interconnect architecture,the performance simulation and analysis of the traditional 3D ONo C architecture is carried out.In addition,the high-capacity three-dimensional ONo C is optimized from three aspects: chain-building scheme,communication strategy and topology.The details are as follows:1.Performance simulation and analysis of traditional 3D ONo C communication architecture.The influence of network dimension,information packet length,network size and traffic pattern on threedimensional ONo C based on optical circuit switching and time division multiplexing is studied.It also analyzes the main bottlenecks that hinder the 3D ONo C communication speed and network capacity.The research results show that,compared with the two-dimensional architecture,the three-dimensional ONo C can not only make the interconnection network faster speed and better throughput performance,but also meet the needs of large-scale chips on integration and performance better.However,the traditional 3D ONo C based on optical circuit switching is still weak in adapting to the growth of network scale and the complexity of traffic patterns.And the traditional time-division multiplexed 3D ONo C is also sensitive to the network scale,but it can shield the complex traffic patterns from communication performance.2.Large-capacity 3D ONoC optimization and design.First,in order to improve the chaining efficiency of optical circuit switching 3D ONo C,the network state division method based on time prediction is used to make the decision of rebuilding the channel or not,and a dynamic back-off chain-building scheme is proposed.Then,in order to improve the communication efficiency of the IP core within and between the layers,the optical circuit switching mechanism and the time division multiplexing method are complementarily combined,and a hybrid layered communication mechanism with communicating by built-in chain in the same layer and by time division multiplexing method in different layers is proposed.Finally,aiming at improving network connectivity,a three-dimensional ONo C communication architecture based on star cluster structure and three-layer communication method is proposed.The simulation results show that compared with the traditional stop-and-wait chain-building scheme,the dynamic back-off chain-building scheme based on network state partition increases the saturation injection point by 20% in the best case,and the network throughput provides 32.7%.Compared with the optical circuit switching communication mechanism,the hybrid layered communication mechanism increases the saturation injection point by 28.7% in the uniform traffic mode,and the network throughput provides 44.5%.In hotspot traffic mode,the communication performance of the network is basically unaffected.Under the network scale of 256 cores,compared with the traditional 3D Mesh communication architectures,the three-dimensional communication architecture based on the star cluster structure increases the saturation injection points in the uniform traffic mode by 78.6%,and the network throughput is increased by 51.8%.In the hotspot traffic mode,the saturation injection points are increased by 66.7%,and the network throughput is increased by 40.7%.In addition,while improving network connectivity,the three-dimensional ONo C communication architecture based on a star cluster structure also maintains the area cost and optical loss of the interconnect system at a low level.