Research Of Adaptive VOQ Router Design And Head-of-Line Problem In Network-on-Chip

Restricted by on-chip resources,the development of the Network-on-Chip(NoC)faces severe challenges,one of which is the management of congestion.However,congestion itself is not a problem.Instead,it is the Head-of-Line blocking(HoL)that has the bad influence.Only by completely eliminating the bad influence of HoL,the network performance can be guaranteed.Therefore,this article aims at the HoL problem of NoC,and researches from two aspects,which are reducing the appearing of HoL and eliminating the influence of HoL.The main work of the thesis is as follows:(1)Aiming at the congestion problem in NoC and reducing the appearing of HoL from the beginning,we design an adaptive VOQ router architecture.By separating the packets for different outputs in the buffer,the first kind of HoL is eliminated.With the use of the head flit helping propagation mechanism,routing calculation module can select the output direction adaptively based on congestions,which implements the adaptive routing for VOQ routers on the hardware.With VOQ mechanism,working together with the adaptive routing packets,it can greatly reduce the the appearing of HoL in NoC.(2)Aiming at the HoL problem of VOQ routers,we design an improved VOQ router architecture,which can eliminating the influence of HoL.Keeping VOQ mechanism characteristics unchanged,we design a hybrid structure of bidirectional FIFO queues,which can read packets adaptively in a single queue and transfer particular traffic first,as well as its downstream path is uncongested.The congestion state of the downstream path is achieved by the head flit helping propagation mechanism.Through innovating the switch arbitration module,we implement reading packets in a single queue adaptively,without any increase in the critical path.With VOQ mechanism,working together with the adaptive reading packets,it can greatly eliminate the influence of HoL in NoC.(3)We Simulate and analysis the experimental results of the proposed adaptive VOQ router based on hybrid-bidirectional queues.Experimental results show that the proposed architecture balances the network load and achieves lower network average delay,along with higher network throughput,which significantly improves the network performance.While its area and power consumption is acceptable,compared with the based virtual channel router and traditional VOQ router.