[ros1-legacy] Higher CPU total usage when disabling the depth camera

[captain-yoshi]

Required Info
Camera Model	D415
Firmware Version	5.16.0.1
Operating System & Version	Ubuntu 20
Kernel Version (Linux Only)	5.15.0-119-generic
Platform	PC
Librealsense SDK Version	2.55.1.0
Language	C++
Segment	Robot
ROS Distro	Noetic
RealSense ROS Wrapper Version	2.3.2

Issue Description

# Working correctly
$ roslaunch realsense2_camera rs_camera.launch

# Slow GUI, due top high CPU -> polkitd
$ roslaunch realsense2_camera rs_camera.launch enable_depth:=false

When starting the color and depth camera, the GUI interface is responsive, the average CPU is 91% while the realsense-ros package uses 34% .

When disabling the depth camera, the GUI interface slows down, the average CPU bumps up to 192% even though the realsense-ros process uses 15%. The /usr/lib/policykit-1/polkitd --no-debug process is now 50% (contrary to 2% when not disabled). This happens everytime. Tried rebooting the system and the camera.

You can inspect the ressources log with atop:
atop_logs.zip

Depth = ON

Depth = OFF

[MartyG-RealSense]

Hi @captain-yoshi There have been a couple of past cases where this phenomenon has occurred. As there is not a known fix, I would recommend having the depth stream enabled but setting it to a low resolution and FPS speed so that it is publishing but not having a significant effect on CPU percentage usage.

You could do this by launching with a custom stream configuration like the command below, which sets depth to 640x480 and 6 FPS, and color to 640x480 and 30 FPS.

roslaunch realsense2_camera rs_camera.launch depth_width:=640 depth_height:=480 depth_fps:=6 color_width:=640 color_height:=480 color_fps:=30

If you need to user a higher resolution for color then simply customize the values of the color parameters in the launch instruction. For example for 1280x720 color:

roslaunch realsense2_camera rs_camera.launch depth_width:=640 depth_height:=480 depth_fps:=6 color_width:=1280 color_height:=720 color_fps:=30

[MartyG-RealSense]

Hi @captain-yoshi Do you require further assistance with this case, please? Thanks!

[captain-yoshi]

Lowering the depth resolution helps reduce the CPU a bit. Thanks.

[MartyG-RealSense]

You are very welcome, @captain-yoshi - thanks very much for the update!