Songran Liu

Songran Liu

Northeastern University, China

ROS2 ISSUES

Used commands:

  1. ros2 topic Command Line Tool

    • ros2 topic list

      $ ros2 topic list
/greetings
/parameter_events		# also automatically started when you start the node. Every time a change has been made to parameters for this node, the change will be published to this topic.
/rosout							# all nodes automatically have a publisher to this topic when started. When you print a ROS2 log, the log will be sent to that topic.

    • ros2 topic echo /* : Print the data going through a Topic

    • ros2 topic info/type /* : Get more details about a Topic

      $ ros2 topic info /greetings 
Type: example_interfaces/msg/String
Publisher count: 1
Subscription count: 0

    • ros2 topic pub /* : Publish to a topic from the terminal

    • ros2 topic hz /* : Check if your publishers/subscribers manage to follow the rhythm

    • ros2 topic bw /* : Check how much data is going through a Topic

      $ ros2 topic bw /greetings 
Subscribed to [/greetings]
271 B/s from 5 messages
    Message size mean: 44 B min: 44 B max: 44 B
243 B/s from 10 messages
    Message size mean: 44 B min: 44 B max: 44 B
235 B/s from 15 messages
    Message size mean: 44 B min: 44 B max: 44 B

    • ros2 node info /* : Find topic info directly from a node’s name

      $ ros2 node info /greetings_publisher 
/greetings_publisher
  Subscribers:
  Publishers:
    /greetings: example_interfaces/msg/String
    /parameter_events: rcl_interfaces/msg/ParameterEvent
    /rosout: rcl_interfaces/msg/Log
  Service Servers:
  Service Clients:
  Action Servers:
  Action Clients:

  2. Ubuntu

    • pgrep -l test_mul...
    • pidstat -p #PID 1

I. Publishing is slow in MutliThreadedExecutor (Dec 8, 2020)

Related Issues: