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.

Everytimes things seem easier , for you , coders , compiling included , tried once compiling linuxcnc , 12 years ago,gave up ,
as i always found some up-to-date debs and managed with missing dependencies .
No non lts option ? hmm , i guess where armbian step aside ''standard support'' is the broken pcie of first opi4.
I did not test the whole compatibilities yet , ethernet is one and could i end up with problem ,does log error for the missing NPU (weird it's on b ?! ).
May i suggest , dont do upgrade , or know what you choose to with your rt image ,as i did broke repo & reinstall,quick fix .
Tar.xz does wonders , 4.7gb to 1 ,amazing .
isol 2-5 , i'll check , tested a lots of combinations , lazy me , did not note them ...
Armbian-config use to have cpu settings options ? it's gone?

Did you change the the dtb in /boot/armbianEnv.txt
fdtfile=rockchip/rk3399-orangepi-4-lts.dtb
-> fdtfile=rockchip/rk3399-orangepi-4.dtb
+ extraargs=isolcpus=5 or 2-5

And what result do you get?

To prevent the rt kernel from getting overwritten you could hold the package with: sudo apt-mark hold packagename

royka wrote:

And what result do you get?

Did all those,yes ,first change i made ,fdtfile=rockchip/rk3399-orangepi-4.dtb, simply would not make it to login prompt ,i test again ,it hang led blink ,there is usb power but frozen kernel.
lts is fine ,no change needed .
I never tried another armbian opi4lts image on this 4 ,your's only.
Results are not good , is it the gpu acceleration or rt or both ,i get random results ,lags,oops & hangs sometimes at boot & shutdown with isolcpu ,
system is snappy without cpu isolation ,did tested a lot , probably too many isolcpu combinations ,had fun installing all the lightest i could,one is jwm ,minimal desktop.
Logs i saw show knowed es8316 sound error at boot ,and memory allocation or cache management at shutdown (when oops&hangs) .
isolcpu=4,5 seems the best (or a little more stable) ,with wifi/ethernet(7i92 )/3 x glxgears ,
histogram state base/servo 48/37uSec stable, open firefox ,it spike to 120/130 .
Never detailed , it's an opi4 4gb 16gb emmc v1.4 ,
tested here from emmc install .Well powered(branded 4Amp ps) with heatsink&fan .

@roya , if you work on this image or optimize another one 6.12 , i'll be glad to test some more , and i guess there should be some fixes in 6.12 , or regressions...
Thanks for sharing your work .

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.

 
from then I tried so much and still couldn't compiled a real-time image which linuxcnc be installed and its latency shows up.
Could you please guide me after placing patch (patch-6.6.63-rt43) in the /patch/kernel/archive/rockchip64-6.6 and configuring fully preemption option, what changes do I need to do?