PREEMPT_RT Kernel for Jetson

We provide a PREEMPT_RT kernel for Jetpack 6.1. This kernel is recommended only for use with robot manipulators, as many manipulator manufacturers recommend a low-latency kernel for interfacing with their robots.

Install PREEMPT_RT kernel from apt server

  1. Follow instructions from Developer guide to install PREEMPT_RT kernel on Jetson.

  2. Check if PREEMPT_RT kernel is active by running the below command which should return text that contains PREEMPT RT.

    uname -a

Reduce Ethernet Latency

When connecting your robot through Ethernet, it’s helpful to reduce the latency by running the following commands.

  1. Install Ethernet tools.

    sudo apt-get install ethtool net-tools

  2. Bring down the Ethernet interface.

    ifconfig eno1 down

  3. Tune the rx-usecs parameter using ethtool.

    sudo ethtool -C eno1 rx-usecs 64

  4. Bring up the interface.

    ifconfig eno1 up

  5. Check if the new value is reflected as rx-usecs: 64 in the output of ethtool.

    ethtool -c eno1 | grep rx-usecs

  6. Now ping your robot’s IP address (<ROBOT_IP_ADDRESS>) to check the latency.

    sudo ping <ROBOT_IP_ADDRESS> -i 0.001 -D -c 10000 -s 1200

Uninstall PREEMPT_RT kernel

  1. Remove kernel headers and modules

    sudo apt remove nvidia-l4t-rt-kernel nvidia-l4t-rt-kernel-headers nvidia-l4t-rt-kernel-oot-modules nvidia-l4t-display-rt-kernel

  2. Reboot your machine

    sudo reboot

  3. Verify the kernel version does not include PREEMPT RT.

    uname -a