Non-ROS Threads

The thread configurator can also manage scheduling for threads that are not part of any ROS 2 executor — for example, sensor driver threads or custom worker threads. Threads created through the helper below report their information to cie_thread_configurator automatically, without requiring a ROS node.

Usage

Use cie_thread_configurator::spawn_non_ros2_thread instead of std::thread to create the thread:

#include "cie_thread_configurator/cie_thread_configurator.hpp"

// Instead of:
//   std::thread t(worker_function, arg1, arg2);

// Use:
auto t = cie_thread_configurator::spawn_non_ros2_thread(
    "worker_thread_name",   // unique thread name (used as the YAML id)
    worker_function,        // thread function
    arg1, arg2);            // optional arguments

t.join();

The thread name passed as the first argument must be unique among all threads managed by the configurator, and must match the id field in the non_ros_threads section of the YAML configuration.

CMake

Add cie_thread_configurator as a dependency:

find_package(cie_thread_configurator REQUIRED)
ament_target_dependencies(your_target cie_thread_configurator)

YAML Configuration

Configure non-ROS threads under the non_ros_threads section. The fields are the same as callback_groups, except id is the thread name instead of an auto-generated CallbackGroup ID. All scheduling policies, including SCHED_DEADLINE, are supported.

non_ros_threads:
  - id: worker_thread_name
    policy: SCHED_FIFO
    priority: 85
    affinity:
      - 3

See the YAML Specification for the full field reference.

Prerun Mode

Non-ROS threads created with spawn_non_ros2_thread are also discovered by the prerun node and included in the generated template.yaml.

Tip

The cie_sample_application package includes sample_non_ros_process, which demonstrates using spawn_non_ros2_thread in a standalone process with no ROS 2 node:

ros2 run cie_sample_application sample_non_ros_process