Research Of On-Chip-Network Routing Based On The Wormhole Switching

The scaling of microchip technologies has enabled large scale system-on-chip. Buses and point-to-point connections would not adapt the continuous development of system-on-chip. On-Chip-Network is easy to extend the address space,and it can provide good parallel communication ability; using packet switching as basic communication technique and adopting Globally Asynchronous Locally Synchronous communication mechanism will completely slove the problem caused by on-chip-bus from the view of architecture. Transmission delay is the important criterion of nerwork performance, which is mainly resulted by the routing algorithm of On-Chip-Network, affecting the performance of On-Chip-Netwrok.Firstly, analyse some issues in on-chip-network routing algorithm based on wormhole switching. the demension-ordered can't move until the link is free when occur contentions. Hot-potato router can arbitrarily choose one free output port without waiting, but has the problem of livelock. Both of them will increase the network delay.Secondly, Based on the contention awareness singals to routers which are closed to each other, proposed a contention-foresee adaptive routing algorithm and analyse its rationality that can decrease the network delay; also designed a on chip router which can support the adaptive aggorithm based 2-D mesh, and the logic structure has been given.Finally, based on the deeply research on the property of SystemC which simulate On-Chip-Network, developed a simulation program using SystemC. The simulation represents the multilayer property very well. At the same time, it can easily make simulations with defferent routing algorithms. The program also supports the buffer size modification of the router, so it is a On-Chip-Network simulation program with adjustable parameters. Under the condiction of the same buffer space, the transmission delay of adaptive routing is proved better than hot-potato routing by simulation experiment, it is also proved better than traditional dimension-ordered, especially in the case of multiple contentions. It indicate that contention foresee routing algorithm effectively reduce the rate of link contention and decrease the network delay.