  Autonomous applications are typically developed over Robot Operating System
2.0 (ROS2) even in time-critical systems like automotive. Recent years have
seen increased interest in developing model-based timing analysis and schedule
optimization approaches for ROS2-based applications. To complement these
approaches, we propose a tracing and measurement framework to obtain timing
models of ROS2-based applications. It offers a tracer based on extended
Berkeley Packet Filter (eBPF) that probes different functions in ROS2
middleware and reads their arguments or return values to reason about the data
flow in applications. It combines event traces from ROS2 and the operating
system to generate a directed acyclic graph showing ROS2 callbacks, precedence
relations between them, and their timing attributes. While being compatible
with existing analyses, we also show how to model (i)~message synchronization,
e.g., in sensor fusion, and (ii)~service requests from multiple clients, e.g.,
in motion planning. Considering that, in real-world scenarios, the application
code might be confidential and formal models are unavailable, our framework
still enables the application of existing analysis and optimization techniques.
