Thermal Management For Three Dimensional Network On Chip

The rapid development of integrated circuits makes the transistor density and operating frequency become higher and higher,as well as multi-core technology makes the number of integrated cores on a single chip be increasing,3D NOC is regarded as an efficient way to connect multi-core.With the transistor density and operating frequency becomes higher,the chip's power dissipation and heat dissipation problems are increasingly prominent.Therefore,3D NOC thermal management has become a hot topic in academic research.Based on the a 8*8*4 3D NOC,a prediction method,frequency adjustment method and temperature-adaptive routing method were established based on the temperature information of the network nodes,which were important for the thermal management of 3D NOC.The main work and innovation of this paper are as follows:1.A temperature prediction method was proposed.According to the heat dissipation characteristics of 3D NOC,the one-dimensional steady-state heat conduction principle in heat transfer theory was used to calculate the corresponding thermal conductivity R and C values,and the temperature prediction model was established.The temperature prediction method has the characteristics of strong practicability,simple operation,low cost and high precision.The experimental results show that the maximum absolute error of the temperature prediction method was less than 0.15 ?,and the average absolute error was only 0.08134 ?.Compared with other temperature prediction methods,the mean absolute error was reduced by 45.77%2.A frequency adjustment method was proposed.In order to make full use of the heat dissipation path of 3D NOC,the adjustment area was divided into columns.When the node temperature inside the column area exceeds the preset value of frequency adjustment,it will reduce the operating frequency of all nodes in the area and prevent the temperature from being too high.As the adjusted network nodes were at different operating frequency,this paper also designed asynchronous FIFO for communication.The experimental results show that the peak temperature difference before and after frequency adjustment was 12.394 ? and the performance cost was only 2.21%.Compared with similar frequency adjustment method,the decrease of peak temperature was increased by 19.7%3.A temperature-adaptive routing method was proposed.The method generates the transmission direction according to the relative position of the source node and the destination node in the network,and then selects the direction with the lowest temperature of the next hop according to the temperature information of the router.As the method was a shortest path routing method,this simplifies the design without deadlock.The experimental results show that the method can get low average network temperature and network delay,Compared with XYZ routing method under the same conditions,the average temperature dropped by 0.342 ?,the average temperature standard deviation decreased by 21.8%,the average network delay decreased by 96%.4.The above thermal management method is realized on Access Noxim platform.Firstly,the Access Noxim platform was analyzed.Based on the study of its code structure,the temperature prediction method,frequency adjustment method and temperature-adaptive routing method were designed and validated.By observing the temperature changes and overhead data of the program,the comparison shows the effectiveness of the proposed method.