Modeling, implementation, and analysis of XRCE-DDS applications in distributed multi-processor real-time embedded systems

The Publish-Subscribe paradigm is a design pattern for transparent communication in many recent distributed applications. Data Distribution Service (DDS) is a machine-to-machine communication standard that aims to provide reliable, high-performance, inter-operable, and real-time data exchange based on publish-subscribe paradigm. However, the high resource requirement of DDS limits its usage in low-cost embedded systems. XRCE-DDS is a Client-Agent based standard to enable resource-constrained small embedded systems to connect to the DDS global data space. Current XRCE-DDS implementations suffer from dependencies with host operating systems, target only single processing units, and lack performance analysis methods. In this paper, we present a bare-metal implementation of XRCE-DDS standard on the CompSOC platform as an instance of Multi-Processor System on Chip (MPSoC). The proposed framework includes a hard real-time side hosting the XRCE-DDS Client, and a soft real-time side hosting the XRCE-DDS Agent. A Scenario Aware Data Flow (SADF) model is proposed to capture the dynamism of the system behavior in terms of different execution scenarios. We analyze the long-term expected value for throughput by capturing the probabilistic scenario switching using a proposed Markov model which is experimentally validated.