Poor PhysX performances

[danielemorra98]

Bug description I have a scene with a 4-wheels vehicle on a simple box serving as a ground. The vehicle is controlled through Ackermann Controller. I have have two different setup (from now on COMPUTER-A and COMPUTER-B) in which I run the same simulation with the following difference:

COMPUTER-A has Ros2-Gem checked out at de2d1cdfa68310c6c0d885d65c0d62fa972a4a69 commit (1 dec) COMPUTER-B has Ros2-Gem checked out at ba6a13a0f013f7c58bf5039ea08cca391014f09a commit (10 oct)

With COMPUTER-A when I move the robot (through a custom teleop_twist_keyboard node) it does not look smooth, but it is bouncing on the ground. That is something that does not happen with COMPUTER-B.

Did you modify the way the colliders and/or the Torque actuated on the wheels behave?

Test environment Both COMPUTER-A and COMPUTER-B:

• OS: Ubuntu 20.04
• ROS: Galactic

COMPUTER-A:

• CPU: Intel Xeon Gold 5218
• GPU: Quadro RTX 5000

COMPUTER-B:

• CPU: 11th Gen Intel Core i9-11900K
• GPU: NVIDIA RTX A5000

According to this website the Xeon CPU has about 36% lower single-thread performance. However, I do not think this justifies the significant observed difference in performance.

[michalpelka]

Thanks for raising the issue, could you observe the difference in frames per second between computers A and B? We did some minor changes to VehicleDynamics, but it is not expected to affect the way torque is applied. Could you provide me FPS and videos on robot behavior on Computer-A?

[danielemorra98]

FPS:

• Computer-A: 7-10 fps
• Computer-B: 30-37 fps I was wrong with the GPU card mounted on Computer A. I edited the first message with the right one.

[michalpelka]

Thank you for your reply. Current vehicle dynamics need more than 20 fps to work properly. Correct me if I am wrong, but you are getting such bad performance on Computer-A after activating the vehicle dynamic?

[adamdbrw]

@danielemorra98 if you run any of the Demos (Vacuum, Agricultural one) and disable VehicleDynamics components, does this affect your fps?

Could you please make a comparison and perhaps add a profiler output to help us identify the issue? We have not experienced performance issues with Vehicle Dynamics previously.

Simulations which are set to real time in general do not behave well with low FPS. A feature to help users with low specs use the simulation would be needed - such as stable step execution (lower than real time ratio).

[adamdbrw]

@danielemorra98 did you have some time to look into whether this happens in any of the demos with / without VehicleDynamics?

[danielemorra98]

@adamdbrw Unfortunately I cannot access to the machine anymore. I will ping you again in case I will be able to do in the future. My Apologies