Bus-Aware Multicore WCET Analysis through TDMA Offset Bounds

Timon Kelter1,  Heiko Falk1,  Peter Marwedel1,  Sudipta Chattopadhyay2,  Abhik Roychoudhury2
1Technical University of Dortmund, Germany, 2National University of Singapore


In the domain of real-time systems, the analysis of the timing behavior of programs is crucial for guaranteeing the schedulability and thus the safeness of a system. Static analyses of the WCET (Worst-Case Execution Time) have proven to be a key element for timing analysis, as they provide safe upper bounds on a program’s execution time. For single-core systems, industrial-strength WCET analyzers are already available, but up to now, only first proposals have been made to analyze the WCET in multicore systems, where the different cores may interfere during the access to shared resources. An important example for this are shared buses which connect the cores to a shared main memory. The time to gain access to the shared bus may vary significantly, depending on the used bus arbitration protocol and the access timings. In this paper, we propose a new technique for analyzing the duration of accesses to TDMA-arbitrated, shared buses. We implemented a prototype tool which uses the new analysis and tested it on a set of realworld benchmarks. Results demonstrate that our analysis achieves the same precision as the best existing approach while drastically outperforming it in matters of analysis time.