Section: New Results

Regular interconnection network for HP-SoC architecture

Our Synchronous Communication Asynchronous Computation (SCAC) model is a data-parallel execution model dedicated to the High Performance System-on-Chip. The architecture of this model is composed of huge number of complex routers, called node elements (the NEs), communicating and working in perfect synchronizations. Each NE is potentially connected to its neighbors via a regular connection. Furthermore, each NE is connected to a heterogeneous set of computing groups (clusters) allow asynchronous processing. Each group includes a combination of processors programmable, the PEs (software processing units) and specialized hardware accelerators (hardware processing units) to perform critical tasks demanding the more performance. All the system is controlled by a Network Controller Unit, the NCU. The NCU and The PEs are implemented with the Forth processor.

The synchronous communication in SCAC model is presented by two kinds of communications:

• The NCU/NEs communication. In fact, we defined a hNoC model integrated in the SCAC architecture [31] . This model is based on sub-netting the network of processing nodes which separate the control of communication and processing. From this model, our communication system allows a better management of data congestion in the NEs grid through the broadcast with mask of parallel instructions to activated processing nodes.

• The NE/NE communication which is our last contribution. In fact, we defined the X-net interconnection network which is a regular network dedicated to the massively parallel SCAC architecture. This network interconnects directly each PE with its 8 nearest neighbors in a two-dimensional mesh through a specific router in the NE module.

The aim of these last works is to design a regular NoC for SCAC architecture to allow global synchronization of the system communications and increase high performance in terms of area cost and bandwidth. This network based on IP blocks which offer well flexibility and scalability, was implemented in synthesizable VHDL code that was simulated and targeted Xilinx Virtex6 (XC6VLX240T) board. The difficulty of designing X-net is a compromise between an optimal quality of broadcasting, high bandwidth and important flexibility of use, while reducing power consumption and silicon area.