Can the OPI5 be Configured to Run LCNC?

@kmike Great results. For the CPU fan I didn't make an overlay but made a change to the dts file. I've copied it from the OPi5 plus, but somehow it only compiles with a zero added. Here is a patch do you can edit the temperatures:
 

Hello everybody
I have a pc with a bad latency and I was thinking of changing LINUXCNC to an orange pi 5 that I have, I have never compiled a kernel I am ignorant.
I have installed kmike's image
mega.nz/file/UCMhiZgZ#Qdg-e3CaQBDQQXQ0rN3...dNJfphJSckes99q7FAR8

It starts fine, works fine.
I try to add isolcpus=5,7 but I find that there is no grub installed. In which file should I put isolcpus=5,7 to improve latency?

@angelnu In /boot/armbiEnv.txt by adding the following line:
extraargs=isolcpus=5,7

I am trying to run Linuxcnc on OPI 5 and I get a latency of 75 - 85 us, I am using kmike's image mega.nz/file/UCMhiZgZ#Qdg-e3CaQBDQQXQ0rN3...dNJfphJSckes99q7FAR8.
I tried to use royka's image at mega.nz/folder/78Z3UbRD#Pl8DdWmxLF3CDma21An8gQ for debian bookworm but it didn't start.
I added extraargs="isolcpus=5,7" in the armbianEnv.txt file, and it looks like I am running linuxcnc with realtime kernel.

The error I got on first boot:
ln: failed to create symlink '/boot/uInitrd': Operation not allowed.
update-initramfs: Symlink failed, moving /boot/uInitrd-5.10.160-rt89-rockchip-rk
3588 to /boot/uInitrd
renamed '/boot/uInitrd-5.10.160-rt89-rockchip-rk3588' -> '/boot/uInitrd'.
update-initramfs: Armbian: done.

I don't know what it means.

Any ideas or suggestions to improve latency?

 

Same latencies here.... I guess it may be caused by running from an SD card? I have ordered a NVME SSD, and will test again when that is installed. 
Another thing I noticed, is that when using Cinnamon as the desktop instead of XFCE, the performance seems to improve. Still some latency spikes here and there, but overall my system seems to perform better with Cinnamon.  I also tested other desktop environments, like LXQT and Gnome, but those seem to perform worse than Cinnamon.
 

I have tried it on a NVME 2080 that I had and it is not too much difference about 20 us less, with the kmike image from mega.nz/file/UCMhiZgZ#Qdg-e3CaQBDQQXQ0rN3...dNJfphJSckes99q7FAR8, I have tried to install the royka images from mega.nz/folder/78Z3UbRD#Pl8DdWmxLF3CDma21An8gQ, and it does not boot any debian or ubuntu image.
I am trying to make an armbian image but I don't have enough knowledge I have managed to create an image but without RT patch.
I try to put a patch from mirrors.edge.kernel.org/pub/linux/kernel...jects/rt/5.10/older/, but the armbian image is 5.10.160 and there is no RT patch 5.10.160 the closest is 5.10.162 and 5.10. 158 , I have copied the *.pach file in build/userpatches/kernel/rk35xx-legacy to try to compile only the kernel with sudo ./compile.sh BUILD_ONLY=kernel KERNEL_CONFIGURE=yes BOARD=orangepi5 BRANCH=legacy, it gives errors and does not compile.
I don't know where to go from here.

Sorry for my English
Translated with DeepL.com (free version)

Intrigued by the quite significant latency differences between XFCE and Cinnamon, I did a few more experiments. In summary the Max Jitter with XFCE is around 50 us for both the Servo and Base threads. Under Cinnamon I see around 2 us for the Servo thread and 9 us for the Base thread, which are fantastic results However, under Cinnamon the processors show a very heavy load, depending on graphic activities on the screen. Simply running system monitor full screen and displaying the processor load graphs, shows that the load for most processors is around 90%, while resizing the window results in a equivalent reduction of the processor load. Under XFCE the graphs stay low all the time. To me it sees that Cinnamon has problems handling graphics, which really consumes extreme processor resources. However, it does not affect the excellent latency results......

@angelnu Sorry a bit of a late reply, but in the screenshot you sent, it shows "no_isolcpus" which indicates that you didn't isolate any CPU.
It seems like something went wrong with adding the following line to armbianEnv.txt:
extraargs=isolcpus=5,7

royka wrote:

@angelnu Sorry a bit of a late reply, but in the screenshot you sent, it shows "no_isolcpus" which indicates that you didn't isolate any CPU.
It seems like something went wrong with adding the following line to armbianEnv.txt:
extraargs=isolcpus=5,7
 

I have tried it later with isolcpus 5.7 and I do not get other difference. With the image of kmike: Kenel 5.10.160 RT and ISOLCPUS = 5.7.
 

With the image of armbian kernel 6.8.0-RC1-edge, without real time but with isolcpus = 5.7. Something better in Servo Thread behaves, I have a Orange Pi 5.
 
 

That's strange, maybe you can try this kernel on another image:
drive.google.com/drive/folders/1JglCIPKv...roZcjOvr?usp=sharing

I'm using this kernel with the Debian Bookworm Image from the site of Orange Pi and HW acceleration works, although while watching YouTube videos the latency increases a bit, but not so much as yours for sure.