executors behind warning

[jmatejcz]

Describe the bug
No matter which executor MultiThreadedExecutor or SingleThreadedExecutor is used in manipualtion demo, following warning appears:

MultiThreadedExecutor is 1.47 seconds behind. If you see this message frequently, consider switching to SingleThreadedExecutor.

It does not produce any bugs that I m aware of, but can impact performance

To Reproduce
Steps to reproduce the behavior:

1. Run manipulation demo
2. Check out logs

Platform

• OS: Ubuntu 24.04
• ROS 2 Jazzy

Version
414c328

[maciejmajek]

Unfortunately, there is only so much we can do using the ROS 2 Python API. The MultiThreadedExecutor is extremely laggy, so the SingleThreadedExecutor is preferred for most use cases.

However, the SingleThreadedExecutor can fall behind when too much work is assigned to a single thread. Because message callbacks and service calls are blocking, the executor may fail to process all callbacks in time, at which point warning logs will appear.