[split] Real Time Kernels discussion

[uglymusic]

@"uglymusic" let's continue the discussion on Real Time (RT) kernel for Pi here.  Some history first.

Prior to SO 1.2.x, AK delivered RT SO images but this was not sustainable. SO 1.2.x became Ubuntu based with standard kernel until the arrival of the Ubuntu RT kernel this year.  However the RT kernel was for X86, not Pi.

As an aside, AK had an ambitious project to customise RT kernels for individuals but it stalled.
https://www.snakeoil-os.net/forums/Threa...el+builder
If the project is revived, I would like to see RT kernels sold for profit because it is resource intensive and SO could do with income.

For the Pi, start with this
https://forums.raspberrypi.com/viewtopic.php?t=344994

Then, use the info from here to look at the Make parameters
https://docs.ros.org/en/foxy/Tutorials/M...ROS-2.html
Try removing the unnecessary parameters for wireless, GPU, crypto, foreign hardware etc. This edit is slow but it can reduce the Make  process time by a lot.  However, you can also cause the boot to hang if too much is removed.

I have not tried with the Pi, but I did find problems with the ROS guide and other web resources. I will try to help but am illiterate in Linux. I can Google my way to to find potential fixes, but cannot guarantee that things will work.

*** Forgot to add this important point.  I backup my SO instance using Clonezilla before starting.  Things will and do go wrong. Recommend cloning SD card before starting.

*** A difference between the Intel NUC and Pi is the tweaking of the BIOS.  In the NUC, can switch off unnecessary things like Hyperthreading, virtualisation, power savings, all of which can impact SQ.  There are no BIOS tweaks for the Pi.  May have to tweak things in Make?

Thank you, @"Snoopy8". This looks like the pointer I need, although I suspect it'll be Christmas reading and possibly another opportunity for indigestion