A Mixed Timing System-Level Embedded Software Modelling and Simulation Approach

System-level software modelling and simulation have become important techniques for real-time embedded system early design space exploration. However, the timing accuracy issues have not been solved well in current methods, which produce unrealistic results or large simulation overheads. In this paper, we propose a mixed timing modelling and simulation approach to decouple conventionally interdependent software timing modelling and simulation into two separate phases. This approach enables (1) mixed software timing information granularities and annotation methods at the modelling stage for performance and accuracy trade-off (2) good software preemption and hardware interrupt handling timing accuracy at the simulation stage without sacrificing simulation performance (3) varying system run-time status observability and simulation speed for efficiency trade-off. Experiments demonstrate that our approach has flexible simulation performance trade-offs and good simulation timing accuracy. The measured results indicate that hardware interruption and software preemption problems are also solved by our approach.