A Research Of Zero-Copy Communications Technology In Real Time Environment

To improve the efficiency of network commucations, the cost of communications must be reduced. The zero-copy technology can reduce the cost of data copying in communicate process. It is an important researching area of high performance communications. There is a lot of research and technology development about the area in the world. The presented zero-copy communications protocols can not satisfy the need of real time communications. So, it has academic meaning and applied value to research and develope zero-copy communications protocol in real time environment.The zero-copy communications in real time environment-RTZCP is a lightweight protocol technology for cluster system. It is fit for the Linux environment; sustain the hard real time control scheduling provided by RTAI.RTZCP turns the zero-copy communications into reality by this way: using direct mapping way to send data in the sending end; using direct mapping way to receive the non-fragmentated data or single-copy way to receive the fragmentated data in the receiving end. RTZCP provides the interface for network communications and communications real time scheduling. RTZCP has these technologies: a new network cache manage system base on the rtskb data structure, new rtsocket interface, repeated mapping way used to send the fragmentated data, the traffic smoother layer added on the RTMAC layer to control the flux, new fragmentated data collecting way in the receiving end.The test result has shown that RTZCP can protect the real time quality of communications, has greatly improved the efficiency of transferring the non-fragmentated data packet, has some improved the efficiency of transferring the fragmentated data. The test result also shows that RTZCP can assure the steady real time communications efficiency when there is non-real time communications.