Quick Start: Enable Real-time Kernel in 5 Minutes
Need a system with near-instant response on Ubuntu 24.04 LTS? You no longer have to build the kernel manually. Canonical has integrated the RT package into Ubuntu Pro, which is free for personal use on up to 5 machines.
Step 1: Get Your Token
Go to ubuntu.com/pro to register an account. Then, copy the Token from your Dashboard.
Step 2: Run the Commands
# Update package list
sudo apt update && sudo apt upgrade -y
# Link the machine to Ubuntu Pro (replace <TOKEN> with your code)
sudo pro attach <TOKEN>
# Enable Real-time Kernel
sudo pro enable realtime-kernelStep 3: Verify the Results
sudo reboot
# After rebooting, check the kernel version
uname -aIf the result shows the PREEMPT_RT suffix, your system has officially switched to real-time mode.
Why Does Your Project Need a Real-time Kernel?
I once struggled while programming a robotic arm using ROS2, which is a common use case when installing Ubuntu Server on Raspberry Pi 5 for edge computing. Even though the simulation algorithm was perfect, the robot would occasionally stutter or vibrate slightly during real-world execution. The cause wasn’t the code, but the default Generic Kernel.
A standard kernel prioritizes multitasking smoothness. It tries to balance resources between the browser, music, and background processes. This creates significant Jitter (latency variation), sometimes reaching tens of milliseconds.
With PREEMPT_RT, high-priority tasks have the right to “interrupt” the CPU immediately. This makes a world of difference:
- Robotics (ROS2): Keeps control loops stable at high frequencies like 1000Hz.
- Industrial & CNC: Controls stepper motors with microsecond (µs) precision.
- Pro Audio: Completely eliminates pops/clicks when processing virtual instruments at low buffer settings.
Advanced Configuration: Optimizing Real-World Performance
Installing the Kernel is just the beginning. For your software to truly benefit from priority privileges, you need to fine-tune the system, much like hardening your server to industry standards for production environments.
1. Set Real-time Priorities
By default, Linux restricts deep system interference for regular users. You need to grant “VIP” privileges by editing the limits.conf file:
sudo nano /etc/security/limits.confAdd the following lines to the end of the file (replace <username> with your actual username):
<username> - rtprio 99
<username> - memlock unlimited
<username> - nice -202. Measuring Latency with Cyclictest
Don’t guess; use real numbers. The cyclictest tool will show you how effectively the Kernel is performing, and you can complement this with Ubuntu Server management with Cockpit to monitor system resources through a web interface.
sudo apt install rt-tests
# Run a stress test for 1 minute across all CPU cores
sudo cyclictest --mlockall --priority=80 --interval=200 --distance=0 --threads=$(nproc) --loops=60000Pay attention to the Max column. On an optimized Ubuntu 24.04, this number is typically below 50µs. If this number spikes into the thousands, your system is being bottlenecked by drivers or hardware.
Battle-Tested Experience: Avoiding Common Pitfalls
After deploying on dozens of systems ranging from Intel NUCs to industrial computers, I’ve identified three critical points:
Nvidia Drivers: The Enemy of Real-time
Proprietary Nvidia drivers often cause severe conflicts with PREEMPT_RT. If your machine experiences a Kernel Panic at boot, uninstall the Nvidia driver and switch to nouveau. For robotics tasks, using integrated Intel graphics is usually a safer bet.
Wi-Fi Power Management
Power-saving features on Wi-Fi cards can cause sudden latency spikes. In industrial environments, prioritize LAN cables. If you must use Wi-Fi, disable Power Save mode with the following command:
sudo iw dev wlan0 set power_save offUpdate Strategy
Ubuntu Pro will automatically update the RT Kernel when you run apt upgrade. However, if your system is running stably in production, don’t rush the update. While automating security patches is standard practice, real-time environments require extra caution and manual verification.
Conclusion
Official support for the Real-time Kernel in Ubuntu 24.04 is a major milestone for the engineering community. If you are also optimizing Ubuntu 24.04 for other high-performance workloads, this kernel provides a powerful foundation. The process is now simplified to: Connect Pro -> Enable RT -> Configure Limits.
If you encounter any issues measuring latency or configuring drivers, feel free to leave a question in the comments below.
