LinuxCNC running on Ubuntu 18.04 updated to kernel 4.18.12 with Preempt RT

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09 Oct 2018 23:42 #118610 by irakandjii
FINALLY!!!!!! LinuxCNC runs!!!
I was able to patch and compile the current stable kernel 4.18.15. I used the instructions as laid out in :

www.cnc-club.ru/wiki/index.php/%D0%A3%D1...D%D0%B0_Ubuntu_18.04 I used google translate on this and it worked well
and
forum.linuxcnc.org/9-installing-linuxcnc...04-preempt-rt-kernel

I used the current sources: (cdn because that is where I am, your country may be different)
cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.18.12.tar.gz
cdn.kernel.org/pub/linux/kernel/projects...4.18.12-rt7.patch.gz
Compiled flawlessly, only the normal warnings for strings exceeding 1024 bytes

LinuxCNC compiled flawlessly using the instructions from the Russian site and from the installation guides for LinuxCNC.
There were some minor issues with dependencies that were easily resolved. Instructions provided by make and reference documentation.
All tests passed

System info (Coffee lake)
Gigabyte Z370 with i5 8600k (using -j6 option kernel took about 3 min to compile), board has onboard Parallel Port
16 Gb memory
256 Gb SSD

I ran latency-test and have odd results that need investigation, I expected better.
Max Interval (ns)Max Jitter
Servo thread (1ms)101390313903
Base thread4154317317

I believe these numbers are sufficient, but will read further.

Running Linux system monitor tools concurrently indicates no CPU is above 3% occupancy. Leads me to believe there is lots of room for my other applications.

I am using realVNC to access the system remotely, I suspect it may have an impact.. So I will investigate further.
My guess; there is an underlying process consuming some real-time. I will look in this forum for advice.

Next steps: Finish testing then hook up my CNC board
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10 Oct 2018 05:29 #118618 by tommylight
You are on the right path to success, everything looks ok, from latency to having enough power for other applications.
Nice work, thanks for reporting back.
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10 Oct 2018 12:05 - 10 Oct 2018 12:27 #118634 by irakandjii
Thank you.

Very interesting, did a lot of reading last night and better understand the impact of the bios etc. So this morning I went in and turned a few things off in order to experiment.
- turned off all power management funtions
- I am using the onboard cpu based intel 630 GPU, I might have an old graphics card lying around.

So far it is about the same with bios elements turned off, I am curious though and will keep working on it. I will play with the fan monitoring next.

Logged directly into the machine, and I cannot run latency-test or linuxcnc ...file not found. (found in scripts .. )

I see other installations online have an Icon on the desktop with options etc. I might have missed a step, can anyone point me in the right direction on how to get this feature? Is it a problem with reverting back to gnome?
Last edit: 10 Oct 2018 12:27 by irakandjii. Reason: Solved my original problem

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11 Oct 2018 03:32 #118663 by irakandjii
Update: Installed a graphics card I had lying around,
Jitter dropped to servo ~8000, base 10000
Looks like I have a launch.

Now to just get the software running again.

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12 Oct 2018 12:12 #118700 by andypugh
To be honest I would take the more compact arrangement of onboard GPU over a small reduction in latency, especially if you don't intend to use software step generation.
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12 Oct 2018 14:38 - 12 Oct 2018 14:40 #118719 by irakandjii
I will be using a board that uses the parallel port to connect from the pc the controller so I think this is software step generation set-up. But, I have not got quite that far yet in my education to understand the difference.

What you say makes sense though, thank you.

For now, I am trying to really understand what is going on so I can diagnose the inevitable "WTF" happened moments in my future.
Last edit: 12 Oct 2018 14:40 by irakandjii.

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10 May 2019 13:22 #133351 by bkt
not so easy to do!

you must add:
deb http://old-releases.ubuntu.com/ubuntu/ precise main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ precise main universe restricted multiverse

deb http://old-releases.ubuntu.com/ubuntu/ precise-security main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ precise-security main universe restricted multiverse

deb http://old-releases.ubuntu.com/ubuntu/ precise-updates main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ precise-updates main universe restricted multiverse

deb http://old-releases.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse

deb http://old-releases.ubuntu.com/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ precise-proposed main restricted universe multiverse

in your source.list, because precise is now old releases ... + you need to solve no_public key issue with old release so:
sudo apt-get install debian-archive-keyring

Than tcl8.4-dev package required is possible to install only in new releases tcl8.5-dev. But these is quite simple to do:
sudo apt-get install tcl8.5-dev tk8.5-dev

+ printui support is no more avaiable so i use these link:
https://www.ubuntuupdates.org/package/core/precise/universe/base/libgnomeprintui2.2-dev

after these ... without any type of latency issue trik and max abuse of pc (glx 4 windows, youtube 3 video, install multiple addictional package during running latency test) and after 2 hour the result is in these pic.

During upload of the image latency base max-jitter go to 100.000 .... asusB250M, I5 7500 ... I try with isol-cpu and fix smi if i have these issue. But probabily not because the result is after 2 hour of work.

regards
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19 Jan 2020 14:01 - 19 Jan 2020 14:06 #155147 by jferguson
if this is actually working - ie, cutting metal, is it possible to share an iso?
I ask because I'm running 10.04 on a machine to which i just added a modern nvidia card which has only 64 bit driers. I also use machine for 18.04 and 10 hence the nvidia card. solution may be too hang a second monitor on intel xvga port and see if i can get 10.04 to alwasy boot into that port.

I don't think I'm up to doing a full build from source anymore.vwhat do you guys think?
Last edit: 19 Jan 2020 14:06 by jferguson. Reason: better grammar on the installment plan

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19 Jan 2020 19:06 #155172 by andypugh

jferguson wrote: if this is actually working - ie, cutting metal, is it possible to share an iso?


Making a .iso isn't that trivial, as that (nearly) requires all the packages to exist on a public repository somewhere, and to be signed.

If you are running 10,04 then I guess that you have an RTAI system? What hardware interface are you using?
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19 Jan 2020 22:36 - 20 Jan 2020 01:14 #155204 by jferguson
HI,
I'm running a Sherline 2000 with a controller that I built up using a Probotics PBX-2 parallel interface. The other machine is a Chinese 6040 router which came with a parallel controller. it worked from the start so I don't know how they did it.

As an aside, I bought the 6040 on Ebay from an outfit in Shanghai. It arrived in a bale of styrofoam, plywood and cardboard and probably could have been dropped from a plane without any damage.

The only thing I really needed to do to get it going, besides assembly was ease all the sharp edges on the aluminum frame and gantry and install the water pump on top of a homedepot 5 gallon pail full of water. I did have a bit of a hassle before discovering that the lead screws were imperial not metric as had been advertised.

I sent them an email about it and got a nice one back apologizing. then most amazingly, about 6 months later I got another email from them asking how it was going, was I happy with it and had I discovered anything that might improve the product.

I'm 77 and have been buying stuff since i was 12 and have NEVER received anything like this. I was really impressed that they were doing anything more than running these things out the door.

Back to subject at hand.

I had no idea that doing an iso was complex, but what you say makes sense and it sounds like it would actually not be beyond me to to build up my own 18.04 RTAI using the Russian page as a guide along with the additional suggestions here.

I really like LinuxCNC and have been using it 5 years now without any problem. I have a remote shop with above tools and a couple of 3d printers. I design at home either in Creo or OnShape but often do the stl export from OnShape at the shop and then Simplify3D for the slicing, Octopi to control the MakerGear M2.

I have two HP8300 Towers, one at home with 18.04, Windows 10 (for the Creo) and a Nvidia GTX 1070. One at shop basically same except it also has 10.04 rtai with linuxcnc. It has two parallel ports for the controllers. I was using intel onboard graphics on the shop machine which wasn't doing at all well rotating sliced objects in Simplify3D. It did work fine with everything else including 10.04.

So without thinking enough I bought a Nvida 1650 Super, installed it and discovered that 10.04 couldn't handle it. It's a 64 bit card so I doubt that there is anything simple I can do and so went looking for a fresher version of LinuxCNC which might run on an Ubuntu which could live with the card.

So here I am.
I'm pretty sure I can build up the 18.04 RTAI and install the LinuXCNC stuff, assuming it's possible and from what I read above and found in the references I can see it likely is.

Have you done it?

best,

John
Last edit: 20 Jan 2020 01:14 by jferguson. Reason: I can't do anything right the first time.

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