The measured values after the decimal point are truncated.

[hsgwa]

Description

"topic period" and "topic age" values after the decimal point are truncated.
For instance, topic age can be zero in the case of intra process communication.

Expected Behavior

This test package is located here

$ ros2 topic echo /topic_statistics
---
metrics_source: message_age
~snip~
statistics:
- data_type: 1 # Average
  data: 0.6033495235235232
- data_type: 3 # Maximum
  data: 1.221165
- data_type: 2 # Minimum
  data: 0.141677 # 0.141 ms
~~
metrics_source: message_period
~~
statistics:
- data_type: 1 # Average
  data: 9.999780017034087
- data_type: 3 #  Maximum
  data: 11.03389
- data_type: 2 # Minimum
  data: 9.125303
~~
---

Actual Behavior

metrics_source: message_age
~~
statistics:
- data_type: 1 # Average
  data: 0.021038292719842887
- data_type: 3 #  Maximum
  data: 6.0 # after the decimal point are truncated.
- data_type: 2 # Minimum
  data: 0.0 # 0 ms
~~
metrics_source: message_period
statistics:
- data_type: 1 # Average
  data: 9.495270116868728
- data_type: 3 #  Maximum
  data: 24.0 # after the decimal point are truncated.
- data_type: 2 # Minimum
  data: 3.0
---

To Reproduce

I've implemented test case which measures intra process communication.

$ cd ~/ros2_ws/
$ git clone https://github.com/hsgwa/intra_process_ping_latency_test.git src
$ colcon build --packages-select intra_process_ping_latency_test
$ . ~/ros2_ws/install/local_setup.bash
$ ros2 run intra_process_ping_latency_test ping_test
$ ros2 topic echo /topic_statistics # in another terminal

System

• OS: Ubuntu 20.04.1 LTS (Focal Fossa)
• ROS 2 Distro: Rolling