scene slowing down on interaction with two forcefeedback devices

We observed that frame rates drop rapidly when two haptic devices are interaction with the scene, especially on the same model. The scene works smoothly with only one haptic device.

In our scene we used two <LCPforcefeedback>, each LCP is mapped to one haptic device. The haptic device drivers we used are based on the original Sensable plugin. An example of my scene file can be found here: https://drive.google.com/file/d/1FYkEyLfZss7_GbTAXmd6gfT9hrlA-v9P/view?usp=sharing

Based on the performance stats, it looks like a large amount of time is taken up in the force feedback “computeForce()” function which appears to have all the proper timeouts.

@hugo and @epernod have suggested that the issue may come from the LCP that two LCPs would lock each other thus making the constraint resolution very slow.