The Road to Building a real-time (RT) kernel for my favorite OS, Ubuntu 18.04.4

She’ll be right mate, I just through that in to differentiate between the bios only and UEFI & BIOS bootable ones.

@BeagleBrainz
> Could you try running one of the sims say axis and see how long it takes to load up?
I tried it [attch1], but I don't get that far [attch2]

If I kill -HUP linuxcnc [attch3] is what I see: can't insmod.

> Did you try a latency test to see what figures you got ?
I didn't. I figured to fire up LinuxCNC with my last ubuntu 12.04 settings and see how it (mis)behaves.

> Are you starting LinuxCNC?

Stand by. I must've grabbed dmesg at the wrong time. I'll get another. (requires a reboot because no way to unload linuxcnc after trying it, which I just did to try to run an axis sim)

andypugh wrote:

Once LinuxCNC has crashed and left RTAI modules installed the only way to clean up is a reboot.

Not only that, Ubuntu with the rtai kernel seems to take a Lot longer to shutdown than ordinary. [over 2 min when I walked away, but it had finally rebooted when I returned 5 or so min later; compare to non-RTAI 18.04: ~3 sec, although nothing had been run so there was nothing to "clean up"]

I’d reboot and then try running the sims, that should clear up the kernel module issue. Just let it run it’s course, it just maybe that it takes more than 5 seconds to load, how much memory and swap do you have ?

> Just let it run it’s course, it just maybe that it takes more than 5 seconds to load

I've waited on it 5 minutes seeing only "Starting LinuxCNC" in the console. [At that point I give up and try to Ctrl-C (nothing) and finally kill -HUP the process.]

> How much memory and swap?

2GB ram, 2GB swapfile.

Dmesg output before and after linuxcnc startup are attached.

IMHO you really need to try running a latency test.
Otherwise you could just be barking up the wrong tree.
That’s why it’s been suggested trying one of the Mint images and running the latency test prior to installing. You’ll get a feel if you have the right machine. Or Debian wheezy might be the best solution.

I ran 'latency-test' and the result is interesting only in the sense that it shows the identical behavior to linuxcnc when run: it does not open a window!

I suspect now that the apps are running fine but that something is wrong with my windowing. Other apps (firefox, etc.) open fine.