Using Ubuntu low latency & real time kernels

[Snoopy8]

Ubuntu 24.04 comes with both low latency and real time kernels, potentially improving SQ.

Suggest adding an option within SnakeOil tab to set the low latency kernel to full preempt.
https://discourse.ubuntu.com/t/fine-tuni...ency/44834
Another option is to enable nohz_full for the CPU's dedicated to the music players using CPUset. 

The real time kernel is available for both AMD and ARM processors.
https://ubuntu.com/real-time
Have a SO option to simplify the process to login to Ubuntu Pro and get the Real time kernel. 

Just in case people are not aware, Ubuntu Pro is free and the RT kernel can be downloaded free for use on 5 instances.

[Snoopy8]

Had an initial look at the tweaking options and they are not compatible with CPUset, and less friendly. 

My CPUset journey has been posted here
https://www.snakeoil-os.net/forums/Threa...-processes
https://www.snakeoil-os.net/forums/Threa...untu-22-04
However, I have come back to using the SO simple  version. Perhaps it is time to drop CPUset? 

Using pre-empt=full, nohz_full on CPUs dedicated to the music player and proper IRQ affinity settings (dedicate a CPU for the music output IRQ, shift other IRQS to other CPUs ) could potentially make SO sound even better.   Ideally, SO should hide the complexity of setting this up, providing options to: 

• enable RT kernel (using Ubuntu Pro)
  
• Dedicate CPU(s) to music player
  

[Snoopy8]

Just a note for those trying to install the Ubuntu real time kernel yourself.  I just used this on my Pi5.

1. Login to Ubuntu Pro, and go "Your Subscriptions" tab
   
2. In free personal token, copy the command "sudo pro attach xxxxxx" where xxxxx is a token
   
3. On Pi5/Pi4, run the above command
   
4. Then run "sudo pro enable realtime-kernel --variant=raspi"
   
5. Reboot
   

In SnakeOil/Linux Kernel tab, you should see the real time kernel and can swap back to original kernel.