(LPT) Debian 12 Latency spikes/unexpected real time delay. Looking for solution.

I will do that most likely on today and inform you about the result.

I remember when i installed Debian 12 last year, i had also the rtai version installed, but maybe i had wrong bios settings at that time and went back to this current installed version (i had a picture of my latency test and and top reads this):

x86-64 on host debian 17.Feb2025
Kernel-release=6.3.0-rt11-linuxcnc
Kernel-version=#2 SMP PREEMPT_RT Mon May1 17:18:20 AEST 2023

So, maybe installing the rtai version will solve the latency spikes. Should i do a fresh install or just download and install the rtai version?

Interesting you ran into so much trouble.
I found linuxcnc the easiest Debian version to use. I put it on my daughters MacBook white and it works perfectly for word processing programs etc. Other Linux versions gave me trouble.

I use samba for sending files from my Macbook (osx) to my plasma table. It works perfectly. It is a bit slow but that doesn’t matter. 

Freecad and svg files are small.

As written in the first post, first uninstall the current LinuxCNC with:
sudo apt purge linuxcnc*

After that install all the deb files, I think that placing these deb files in a separate folder and entering: sudo apt update && sudo apt install ./*.deb will be the easiest way. Otherwise like in the first post

Just started and i have to post because this is a good example how it always goes for me:
1. sudo apt purge linuxcnc*
works, buty doesnt remove Linuxcnc because: (Package 'linuxcnc' is not installed, so not removed)

cncpc@debian:~$ sudo apt purge linuxcnc*
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package 'linuxcnc' is not installed, so not removed
The following packages were automatically installed and are no longer required:
libwpe-1.0-1 libwpebackend-fdo-1.0-1 linux-headers-6.1.0-18-amd64
linux-headers-6.1.0-18-common linux-headers-6.1.0-18-common-rt
linux-headers-6.1.0-18-rt-amd64 linux-image-6.1.0-18-rt-amd64
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Linuxcnc is of course installed. I dont get it, but thats standard for me already:)

I am planning to do a fresh debian 12 install and delete everything what is currently on the system.
Do i understand correctly, after Debian 12 is installed, i need to do this:
sudo dpkg -i (package name here without brackets)
for each deb that is here onelaboratories.us/abc/ and after that reboot and choose the rtai kernel in grub?

Its just unbelievable... why god damn it cant work..
What i did:
1. fresh install of debian 12
2. downloaded every file from onelaboratories.us/abc/
3. went to downloads folder and opened a terminal
4. first i tried "I think that placing these deb files in a separate folder and entering: sudo apt update && sudo apt install ./*.deb will be the easiest way"
NOT WORKING - if i remeber correctly, something is missing
5. then i tried this: sudo dpkg -i (package name here without brackets)
5.1: i started with: sudo dpkg -i linux-headers-5.4.290-rtai-amd64_5.4.290-rtai-amd64-1_amd64.deb
5.2: sudo dpkg -i linux-image-5.4.290-rtai-amd64_5.4.290-rtai-amd64-1_amd64.deb
5.3: sudo dpkg -i rtai-modules-5.4.290_5.3.3-linuxcnc_amd64.deb
5.4: sudo dpkg -i linuxcnc_2.9.4_amd64.deb

Dont ask me why in this sequence. I just did that because no where its described with which deb to start.
As you can see on the pictures there are things missing.
I then tried to open Latency test fom the drop down (xfce) menu but nothing happend, then i opened terminal and wanted to open it through command.You can see the result on the last pictures.

Guys, please tell me what i did wrong.

UPDATE:
i did again a fresh install of Debian 12 and did the same as described in my previous post with sudo dpkg -i (package name here without brackets).
I then opened Synaptic pacakge manager and it showed me a broken package, which was linuxcnc. I clicked on it and did complete removal. Then i updated everything that synaptic made available and then again i did sudo dpkg -i linuxcnc_2.9.4_amd64.deb.
When i do Latency-test, the pc freezes.

I dont get it, but this is the best example of why i just hate linux.

If i did something wrong or without a sequence, then i need to remember, that the only information i got from first post of forum.linuxcnc.org/9-installing-linuxcnc...debs-for-2-9?start=0, is that i have to have Debian 12 installed, without Linuxcnc.
Then i download the DEBs of onelaboratories.us/abc/linuxcnc_2.9.4_amd64.deb
and each of the 4 DEBs i need to install by "sudo dpkg -i (deb name)".

This does not work.
On start up of the machine i get for about 2 seconds the information that you can see on the attached picture.

Not working, one problem after another. I can imagine that you might think i am a complete idiot.
Machine freezes still, but now, after the 4. fresh install and installing debian-12.9.0-amd64-netinst and installing the debs, of course with some missing things messages while installing them, after boot the machine does not even want to move past the motherboard screen. (press del to... press tab to... screen)
Its the 3 full day i am trying to solve the latency problem, but instead i am only getting more problems.
If i would knew i can get samba to work without spending a couple of days "trying" to get it to work, then i would give up with debian 12 and linuxcnc 2.9.x. Unfortunately i know that when i install again wheezy, i will encounter 1000 things that dont work, starting with the clock, then the internet browser that is not anymore supported and of course samba that also needs some special attention by a Linux specialist, that i am not unfortunately.EDIT: after doing 1-2 changes in bios i can enter linux and also do the latency test, but the latency is about 31000 and also freezes sometimes.

Update: After doing 1-2 changes in the bios, i can again enter linux and also do the latency test, sometimes.. I open it and it shows 0 everywhere (intervall, jitter , last interval).
When i close it and open it again, it shows again 0 everywhere, but after a couple of seconds it shows latency as it should. Now i opened glxgears and youtube but the jitter did not change a lot from 23.000 to 24.769.
I will soon connect the machine and test it. If it works without unexpectec realtime delay message on pop up, then its a good sign and maybe i then just need to make some adjustments in bios or grub config.

EDIT: just thought its looking good, but machine just freezes out of nowhere and i just wanted to start linuxcnc and check if its working, but I also get a error message that i knew how to solve with a terminal command, but due to fresh install that command is not anymore in my terminal history, but i get:
Permission denied.
/custom.hal5: waitpid failed hy_vfd vfd
....

So, beside freezing pc problems, i got a new problem to fix. Amazing.

EDIT: i have found the command and now linuxcnc is starting without unexpected realtime delay, axis moving, but it sound a bit strange, but smooth but with small stops between smooth movement. I will try to adjust bios cpu settings.