Research On The Communication Protocol In Cluster Interconnection System Based On Software/Hardware Co-Design

The research work of this dissertation is a part of the Aviation Science Foundation Project, named "A Study on the Avionics Oriented Switch Fabric Technology" (02F53031). In the foreign fourth generation avionics systems, the core of data transmitting network is a cluster system based on switch-fabric interconnects. It is of great immediate significance for national defense construction to study high-speed data transmitting network for the next generation avionics in China. This dissertation focuses on the communication protocol in cluster interconnection system. The details of the dissertation is as follows:Presently, the overhead of data communication control mechanism used in cluster system, which is usually realized by data packet, is very high. We have designed and implemented a token control network (TC-NET). The TC-NET utilizes multi-hierarchical control tokens to control the procedure of communication. Consequently, the communication efficiency was increased obviously.In commercial network, such as gigabit Ethernet, the communication descriptor is usually realized by software. Therefore, in each message transfer, the NIC has to access physical memory at least twice: (1) the NIC gets communication descriptor from physical memory, (2) it accesses physical memory to obtain user message. So the communication overhead in commercial network is high. In this research, by taking advantage of Software/Hardware Co-design, we put hardware communication descriptor in NIC to support data communication. With this support in hardware directly, the NIC need to access physical memory only once for each message transfer. Thus the communication efficiency is improved. The communication delay in TC-NET is 4 microseconds and 19 microseconds in gigabit Ethernet.As a fast communication standard of cluster systems, VIA has obtained widely supports in industry. In TC-NET, we designed and implemented the TC-VIA user-level communication mechanism based on VIA standard through an approach of the software/hardware co-design. The kernel agent in TC-VIA is based on Linux bottom half function. By the kernel agent mechanism, the TC-VIA realizes the zero-copy data communication and the management of software VI queue. Comparing to the implementation of VIA based on software purely, the TC-VIA has a better communication performance; comparing to theimplementation of VIA based on pure hardware, the TC-VIA has a good flexibility and extensibility.We have presented and implemented the dynamic priority real-time communication protocol in interconnection network by hardware method and formed EDF real-time communication network. The communication schedule in real-time system based on commercial network is usually realized by software method and the communication delay is usually measured in milliseconds. We implement real-time scheduling based on the EDF algorithm by hardware logic, and the communication delay is less than 10 microseconds. So comparing to commercial network, such as Ethernet network, the communication performance in the EDF real-time communication network has been improved greatly. The American Raceway real-time communication network has the highest performance in literature we have seen. It also realizes the priority schedule by hardware method, but it is based on static priority schedule. Comparing to Raceway network, the EDF network has a better communication flexibility and throughput. Thus, the EDF network can support irregular message flow communication better.In complex real-time communication network, the hard real-time communication task needs to get multiple communication links at the same time in a real-time data transfer. To realize hard real-time communication in complex real-time communication network, the dissertation puts forward MEDF algorithm (Multi-resource Earliest Deadline First) for feasibility-test of message-flow. The message-flow satisfying the feasibility-test can get hard real-time communication servers in EDF real-time communication network. The complexity analysis of MEDF algorithm shows that the complexity of MEDF algorithm is lowest in both time and space.