Preemptive RT on Jessie or Stretch?

23 Jan 2018 10:01 #104886 by bymccoy
Hi All

The docs only list the RT kernel for Wheezy as the only option - it incidates Jessie is for simulation only and no mention of Stretch.

The buildbot lists the kernel options for all versions, but no obvious dev notes as to whether they’re production ready or not.

I’m having issues with Wheezy not supporting the Intel HD graphics stack, so need Jessie with Backports or Stretch to fix this.

Is LinuxCNC ready for Jessie or Stretch with the Preemptive RT kernel? There’s no mention on the forum - the last posts from early 2016 are quite outdated in the reasoning behind no support (ie the kernel RT patches not being available).

23 Jan 2018 16:45 #104900 by bymccoy
Okay, that's good...

Are these packages in the repository, or just as live disks/installers?

I have a functional OS, plus prefer to do a manual install of the packages vs using the installer.
23 Jan 2018 16:46 #104901 by bymccoy
Haha, read the first paragraph again:

"While they can be used as a live CD and installed to a hard drive, we do not recommend installing this version on production machines at this time."
23 Jan 2018 17:40 #104903 by skunkworks
We need testers... :)

I have been running the stretch iso on real hardware with no issues so far. YMMV
23 Jan 2018 17:41 - 23 Jan 2018 17:49 #104904 by PCW
This test image has been in use for several months with great success.
I can understand the developers caution, and any new OS release will likely have new bugs,
but, if you want a newer kernel and a working packaged system its the easiest current path.

You can of course install (it its available) or compile your own Preempt-RT kernel on most Debian based OS's
(Straight Debian, Ubuntu, Mint, etc) and build LinuxCNC to match, but there no reason to expect this will be any better than the test image unless you need a very new kernel, and of course the exact same cautions apply to your own created installation...
Last edit: 23 Jan 2018 17:49 by PCW.
23 Jan 2018 17:59 #104905 by bymccoy
For embedded kit I prefer to build the image myself, as the live image comes with a lot of cruft. I prefer to start basic and add packages as needed versus stripping them away.

But I'll try upgrading and see what happens :/
26 May 2018 18:13 #111159 by genixia
There is some new urgency to this - Debian drop Wheezy from LTS this month. No-one can responsibly consider Wheezy for a new build.

I'm embarking on a project now that will likely end up with an ethernet connected Mesa card ( wish I could find 7i77E ), as the panel PC I have for it doesn't have any pci slots. I'm looking at Stretch as the contender. I'll let you know what i find.
26 May 2018 18:18 #111160 by genixia
I installed linuxcnc on top of a straight Debian 64bit Stretch distro and latency tests were horrendous, on the same panel PC that had promising latency results with Wheezy 32bit. The vanilla Debian preempt kernel compile contains a lot of enabled DEBUG options, something known to play with latency testing. I tried to compile a recent (4.16.9) kernel, but it exposed compiler errors and failed. I'm installing the test image now, keeping my fingers crossed about latency.
26 May 2018 19:20 #111163 by billykid
I found this card used, kino dh610 i5 T2500 4 GB memory.
installed debian stretch 64, latency just over 5000. servo thread 8 khz no error even using the internet while the cnc works.
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