A Real-time Scheduling Framework for Multi-threaded ROS 2 Applications

Seryun Kang, Jinseop Jeong, Kanghee Kim

http://doi.org/10.5626/JOK.2025.52.1.1

Real-time performance of robot applications operating in the physical world is crucial. In ROS (Robot Operating System) 2, robot applications consist of dozens or even hundreds of tasks. If the end-to-end delay from sensing to control increases, the resulting motion may be delayed, potentially leading to physical accidents. Consequently, many studies have been conducted to analyze and reduce delays in robot applications. This paper proposes a real-time scheduling framework that allows the application of the probabilistic latency analysis method, originally designed for process graphs, to thread graphs. The proposed framework groups callback functions with the same period into a single group based on a global schedule table and creates a thread graph by assigning a dedicated thread to each group. Each thread is then fixed to a CPU core as determined by the table and is scheduled using FIFO. This paper applies the proposed framework to the localization pipeline of Autoware and confirms that probabilistic latency analysis is feasible within this framework.