Results of latency test, list of computers tested for use with LinuxCNC

OrangePi-5 with rt-kernel, in another thread you could find how to build this kernel/image.
I did try to make it harder for that board but it improved the latency, perhaps the same kind effect as idle=poll.
 

Old tv-box I had lying around, S912-2gb. It could be a bit tricky to install.
The emmc of this box is damaged, to be able to boot from sd I'd to write a different u-boot to the sd. This box froze every time while it was reading/writing from sd with the preempt_rt kernel and some cores isolated. Eventually with the boot partition and u-boot on sd and rootfs on usb it performs fine.

Perhaps it works even better when it's installed to the emmc. The servo thread stayed below 10uS until it did IO heavy tasks. ran out of ram.
 

After replacing Mate with xfce and lowering the resolution to prevent it from running out of ram the result is much better.
 
 

Dell optiplex 7050 mini I5-6500 + 8gb ram + 256gb ssd. I made some additional changes, you can read about it on my blog here .
image missing https://cncrouterinfo.com/wp-content/uploads/2023/05/image-4-768x438.png
youtube full hd video + 4x glxgears
Debian 12 

Optiplex 7040 mini i5-6500T + 2x4gb (DDR memory works faster in pairs)

extra boot archs: isolcpus=3 intel_pstate=disable processor.max_cstate=0 idle=poll cpufreq.default_governor=performance i915.enable_dc=0 ahci.mobile_lpm_policy=1 irqaffinity=0 nomodeset quiet

Kernel compiled + config:  mega.nz/folder/T9gCUZCQ#aQDlVgPDAMtaRgF_-Vzd5g

 


 

If you don't mind me asking, how does one put those files to work? I'm not that well versed in kernals

The deb packages are build on Mint 21 so I'm not sure it will install on Debian although Mint is Debian based. For the kernel you'll only need:
sudo apt install ./linux-image-5.15.93-rt58_5.15.93-rt58-1_amd64.deb

The headers the same way, these are needed when you want to compile a kernel module. So you could first try to only install the kernel.

I see you've got the faster 6500 instead of the 6500T, if the latency increases after a while you could check the cpu temperature. It might be due to throttling, if that's the case you could try to disable the turbo.