Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• Installation type:
  • binaries
• Version or commit hash:
  • 2.3.0-1focal.20210225.215848
• DDS implementation:
  • cyclone_dds
• Client library (if applicable):
  • rclcpp

Steps to reproduce issue

Clone test package: https://github.com/k0suke-murakami/multi_thread_sample

git clone git@github.com:k0suke-murakami/multi_thread_sample.git

Build & Run

ros2 run sample sample

Expected behavior

Low CPU usage.
When executed with a single-threaded executor, the CPU usage is almost 0%.

int main(int argc, char **argv)
{
  rclcpp::init(argc, argv);
  rclcpp::spin(std::make_shared<Chatter>());
  rclcpp::shutdown();
}

Actual behavior

Reaches 40% CPU usage in my environment.

Additional information