Optimising the Scheduling of System Level Logical Execution Time Systems

The paradigm of Logical Execution Time (LET) tasks is widely adopted by major tool vendors for designing deterministic and time-predictable software in multi-core systems, particularly in the automotive industry. To extend the use of LET in distributed environments, System Level Logical Execution Time (SL-LET) has been developed to effectively manage communication and delays between networked devices. However, there is currently a lack of open-source tools available for SL-LET, and the task allocation and scheduling problem for SL-LET remains unsolved. To address these concerns, we introduces a novel Integer Linear Programming (ILP)-based optimisation approach for SL-LET task allocation and scheduling, focusing on minimising core utilisation and average system response times. To illustrate the effectiveness of the approach, we benchmark our ILP-based solution against a traditional core allocation heuristic across multiple task sets. Through this evaluation, our approach, when compared to the heuristic, is able to demonstrate average response times that are 26.9% smaller.