| In order to solve the designing deficiency of traditional system on chip (SOC),the network on chip(NOC) was proposed as a new communication model. The global interconnects cause severe on-chip synchronization errors, unpredicatable delays and high power consumption, so the voltage-frequency islands (VFIs) technology based on the globally asynchronous locally synchronous(GALS) model has become a hotspot of current research in the field of NoC. As the perforation and stacked silicon technology has become more sophisticated,three-dimensional NoC is possible to achieve,which can shorten the average distance between processsing cores, lower the power consumption and improve the reliability. This paper proposed the mapping algorithm NVR-VFIs based on voltage-frequency islands, which can reduce the system power consumption effectively.The research of this paper can be divided into four parts. At first, by the analysis of energy consumption of NoC based on VFIs, we build a model of energy consumption based on 3D-Mesh NoC, and define the mapping objective function under the condition of performance constraint. Then under the condition of allowable maximum VFIs division number, allocate the voltages and frequencies to the IP cores and divide the VFIs to find the minimum energy consumption and the IP cores partition plan under the above-mentiond allocation. Then use near convex region selection algorithm to distribute the VFIs to the region of three-dimensional NoC, while insure that the corresponding processing units which the IP cores in the same VFI were allocated to are in the same convex region. This approach can avoid the appearance of isolated voltage islands to reduce the number of conversion interfaces in VFIs to achieve lower energy comsumption. Finally, apply the branch bound algorithm to map the IP cores in each VFI to the corresponding convex region of NoC to reduce the communication power consumption of the system.To evaluate the mapping algorithm NVR-VFIs proposed in this paper, the applications MPEG-4 VOPD, H.264 decoder and E3S public benchmark suite were used in NCR-VFIs mapping algorithm and random mapping algorithm, and they were tested on 3D-Mesh NoC platform of different scale. The experiment results show that the NCR-VFIs mapping algorithm can save energy consumption by 70% compared to random mapping algorithm of single clock domain, in addition, the number of conversion interfaces used by NCR-VFIs algorithm is reduced by 56% compared to random mapping algorithm. |
