Very slow hd image publihser (not image transport) for hd image using rclpy

[HasanFaragRob]

I am writing a ROS2 driver for Basler cameras in rclpy . I have 37 fps hd (1280*720) color stream from pypylon SDK and wanted to publish that data on topic. I observed, it is way slower, after measuring times in python ,we found out that publish times as below

[INFO] [1638433002.797805612] [basler_camera_controller]: 48.58187501667999 ms
[INFO] [1638433002.870013551] [basler_camera_controller]: 54.1074660141021 ms

I see that you use pybind on rcl for rclpy. Maybe the bottleneck there. I did simple check on pybind in general and it is way slower than original implementation. Please guide me if there is a way to have higher publish rate?

Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• Installation type:
  • binary
• Version or commit hash:
  • foxy
• DDS implementation:
  • cyclonedds
• Client library (if applicable):
  • rclpy

Steps to reproduce issue

publish HD image on rclpy and measure timing on publish

[aprotyas]

Hello, I noticed that you're using the Foxy distribution. Note that ros2/rosidl_python#129 will almost definitely help your case (check ros2/rosidl_python#129 (comment) for some primitive results), but it hasn't been backported to Foxy yet. That effort is underway in ros2/rosidl_python#146 and should land soon!

A couple of other threads that may be relevant at best and only insightful at worst:

• slow publishing and performance for custom messages with large arrays rmw_cyclonedds#346
• ROS 2 speed
• DDS Tuning. Some additions were made to this guide following slow publishing and performance for custom messages with large arrays rmw_cyclonedds#346.

Lastly, it may be helpful if you could profile the code and share where the bottlenecks are? Or alternatively, if you could provide an MVP that someone else could use for profiling!