ROS2: Preferred method of making worker threads

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Any help on the code? It is somewhat cryptic for me, I can not see where the thread is created... I would like a fixed node:thread mapping which does not seem unusual to me, think nodes real-time and nodes non real-time. Any plans of adding such an executor?

think nodes real-time and nodes not real-time.

Mixed Real-Time Criticality with ROS2 - the Callback-group-level Executor (slides).

Just add each node to it's own SingleThreadedExecutor, and call spin on each of those executors in their own thread, and you can setup each thread to be a real-time priority thread or not.

The only built-in executor that creates a thread is the MultiThreadedExecutor , see: https://github.com/ros2/rclcpp/blob/3...

And if I would want this thread:node mapping and also reentrant callbacks? Could I spin each MultiThreaderExecutor in its own thread, and the threads created by that executor in its pool would inherit the parent thread's properties?

I don't know, it depends on what priority your operating system gives to new threads. If they are not inherited, then you'd need to make a new MultiThreadedExecutor which modifies the priorities of the threads it creates before using them. But as I said the MultiThreadedExecutor is trivial.

I do not know C++ well... Could you point me to an exact line in MultiThreaderExecutor.cpp where the threads are created?

I do not know C++ well...

That won't mix well with writing real-time safe code...

I already linked to it, the emplace_back : https://github.com/ros2/rclcpp/blob/3...