Programming Time-Predictable Processors with Lingua Franca

Precision-timed (PRET) machines are an alternative to modern processors that provide precise control over the timing of software execution. This paper describes a platform for developing predictable real-time embedded systems that pair PRET machines with Lingua Franca (LF), a recent reactor-based coordination language with temporal semantics. Specifically, we port LF to FlexPRET, a PRET machine with flexible hardware thread scheduling. We evaluate single-threaded LF with a tight control loop style application on four embedded platforms, including the FlexPRET. The results reveal the underlying platform’s timing variability and how LF plus FlexPRET can remedy this timing variability. Finally, we compare single-threaded to multithreaded LF, again concerning timing. The four embedded platforms used are FlexPRET (bare-metal), RP2040 (bare-metal), nRF52 (with Zephyr), and Raspberry Pi 3b+ (with Linux). Our results indicate that FlexPRET with LF is attractive when precise timing is essential.