Real-Time Communication Support for Embedded Linux over Ethernet.
Sang-Hun Lee, Hyun‐Wook Jin · European Symposium on Algorithms · 2008
Many embedded systems are exploiting embedded Linux due to its rich features and device drivers. However, since embedded Linux is inherited from traditional monolithic kernel design, it has limitations to support real-time communication. One such example is that the protocol stacks of embedded Linux are following the bottom half based architecture. The user-level operations of a higher priority process can get delayed while the bottom half handles the packets for even lower priority processes. In addition, the send/recv semantics of traditional protocol stacks are not sufficient to support various real-time embedded applications. In this paper, we aim to design and implement a lightweight protocol stack that can support real-time communication over Ethernet without Linux kernel modification. The proposed protocol, called RTDiP, provides priority awareness, communication semantic for synchronization, and low communication overhead. The experimental results show that RTDiP can improve the communication latency up to 79% compared with TCP/IP. We also show that RTDiP can guarantee the execution time of real-time applications with less disturbance by communication of lower priority process and can provide predictable communication latency to realtime applications.