Analyzing And Optimizing Methods Of NoC Communication Performance

NoC (Network-on-Chip) has been focused by a lot of researchers for years. The NoC solution is used to solve the bottleneck of the on chip communication between processors, to improve the performance of overall system, and to promote the development of high performance computer. In order to improve the efficiency of NoC design and reduce the time-to-market of NoC product, it is important to develop a useful tool to evaluate the NoC performance. Moreover, since the NoC is limited by the on-chip resources, area and power consumption, it is crucial to research the optimization method with various constraint conditions to improve the NoC performance.In this thesis, we make innovative researches on NoC and the main results are shown as follow:1. By analyzing the system characters and the application characters, we propose a modeling method for NoC communication performance. For the wormhole NoCs, a semi-Markov process is developed to describe the work state of router. Then, we analyze the router performance and NoC communication performance based on this semi-Markov process. For the store-and-forward/virtual-cut-through NoCs, each router buffer is abstracted as a queuing system. By modeling the NoCs in this queuing manner, we can calculate the average packet latency of each router and then analyze the NoC communication performance.2. With respect to the constraint condition of buffer resources, a method is proposed to optimize the NoC buffer resources, such that the NoC communication performance is optimized. For the buffer optimization of NoC router, a novel buffer allocation method is proposed to maximize the NoC performance without any additional buffer cost. For the optimization of the buffer of network interface, a novel buffer sizing method is proposed to determine the proper buffer size of network interface, which maintains the data Quality-of-Service while avoids the waste of buffer resources.3. With respect to the constraint condition of bandwidth, we study the influence of bandwidth on the NoC performance, simulate the performance of NoC with different link bandwidth and modify the analytical model for NoC performance. Then, a novel bandwidth optimization method is proposed to determine the bandwidth for all links in NoC, such that the cost of NoC is minimized. Our model also provides the theory basis for the optimization of NoC area and power consumption.4. By analyzing the different resources requirements in different NoC mapping, we propose an ACO (Ant Colony Optimization) based mapping algorithm to minimize the cost of NoC and improve the performance of NoC. Then, we evaluate the effectiveness of our algorithm under the constraints of latency, buffer resources and bandwidth, respectively.5. After analyzing the disadvantages of the common used schedule strategies in NoC, we propose a dynamic schedule strategy and design the corresponding arbiter to implement the dynamic schedule strategy, such that the‘starvation’problem in NoC schedule is solved. Compared with other schedule strategies, our dynamic schedule strategy can improve the NoC performance and minimize the cost of buffer resources in network interface.