Real-Time Kernel with Orange Pi 4 LTS

You can try this image, with desktop and gpu hw acceleration but under 1GB:
drive.google.com/file/d/1PCetphqJUFfS3aL...eD7/view?usp=sharing

royka wrote:

As far as I know it shouldn't matter if you install it during compilation, otherwise it would be fixed with "apt reinstall linuxcnc-uspace".
What do you see with: uname -a ?
What do you see in the terminal when you start with: latency-histogram ?
 

The output of uname -a:
root@orangepi4-lts:~# uname -a
Linux orangepi4-lts 6.12.1-edge-rockchip64 #2 SMP PREEMPT_RT Fri Nov 22 18:00:26 +0330 2024 aarch64 GNU/Linux

and when running latency-histogram I get:
Note: Using POSIX Realtime

and just this, seems like waiting for something and nothing shows up any more

Perhaps something wrong with the kernel config? You could try to install the kernel deb that I uploaded to see if that helps. Otherwise you might need to install more software, just install a complete desktop will be the fastest route to find out.

royka wrote:

Perhaps something wrong with the kernel config? You could try to install the kernel deb that I uploaded to see if that helps. Otherwise you might need to install more software, just install a complete desktop will be the fastest route to find out.
 

I compiled a desktop one and I've installed the deb kernel real time, and that fixed it. I didnt change much in config file, the only change was enabling fully preemption and I added the patch you provided and set the gpu governor to performance.

royka wrote:

You can try this image, with desktop and gpu hw acceleration but under 1GB:
drive.google.com/file/d/1PCetphqJUFfS3aL...eD7/view?usp=sharing

It's laughable...did not worked tweaking & reweaking to modified it for opi4 ...
your image simply worked as is ...lesson learned here..
i dont understand , if armbian image for opi4 lts work on opi4 why the hell armbian link to non lts ?!?
You tell me , because everything seem to be good .
Trying some isolcpu 1,2 , no latency miracle ,should be ok , cutting air .
Let'see if i can install 2.9.3 now.

Good job Roya ..

No idea, also didn't see an option to compile for non lts, sometimes things are easier than they seem
Better to set isolcpus=5 or 2-5 because linuxcnc always takes the last core and the quad core a53 is after the 2xa72

Ideally you would set isolcpus=1 but then you need to set the rt tasks to core 1 manually, via a script or change the source of linuxcnc.