Unexpected realtime delay error message

dannym wrote:

This is a makerspace with many users and has been running tens of hours since upgrading, and this is something reported, I'm not aware of any unusual circumstances.  It threw this error once, and they had to restart their job:
"Unexpected realtime delay on task 0 with period 1000000
This message will only display once per session. Run the latency test and resolve before continuing. "
 

Typically this is just a warning, and the machine just carries on. 

Did the machine stop executing G-code? Lock up? reboot? Turn into a frog? 
 

If that number is correct, it is the servo period missing the timings, so i would first see if the RT kernel is in use:
uname -a

I got reports it threw Following Errors at some point- not right away.

Is it possible the NUC, being fanless, is silently overheating and the BIOS throttles it back and it can't keep up with the delays?  It was in an air-conditioned shop, probably 78F.

Is there any way to check what the status is, like processor temp?

OK, it did reoccur, and gave this while interpreting g-code.  This stopped it and put in the unpowered state, but they were able to Toggle Machine Power and get it going again.  At least that's the account I heard.   It looks like they were surfacing a board, I saw them running a similar thing when I came by.  I believe they said it happened when making an aggressive turn, but these are just regular right angle turns from like 200 ipm.  

When I did come by, they had been using the machine for awhile, and I felt the NUC box- it didn't seem especially warm.  Different job, but I don't think it's running hot and declocking to protect itself.
 
 

Realtime delay won't stop the machine, but a following error (also seem on screen, before the delay) will.

If you get an f-error and then the realtime delay it feels like something might be temporarily locking the machine? I assume that this is a stepper machine? Possibly the STEPGEN_MAXACCEL is too low (it needs to be 25% higher than the axis limit)

Can you run this command (in a terminal):

halcmd show param *.tmax

After LinuxCNC has been running for a long time
and post the results here (along with the CPU clock speed)