Getting Unexpected Realtime Delay on New Install

We'll, it wasn't the OC Genie. It defaults to off. Any other ideas? Is there a way to see if all of the realtime components loaded correctly?

Does it look like something mismatched with the 5i25 and 7i76?

Did you turn off _all_ power management and disable clock speed switching / cstate options in the BIOS?

There really nothing the 5i25/7i76 can do that affects timing.

If you purchased the 5I25 and 7I76 separately, you need to make sure that the 5I25 has the proper
firmware installed

For a 7I76 this means fetching the 5i25_7i76x2.bit firmware file (in 5i25.zip from mesa)and flashing the 5i25:

sudo mesaflash --device 5i25 --write 5i25_7i76x2.bit

that said, it does look like you have the correct firmware based on the dmesg pin list

This looks very familiar.

Looks like your screen saver and/or power management system.

Try this and see what it says.
$ xset -q

should see
~etc etc
Screen Saver:
prefer blanking: No allow exposures: No
timeout: 0 cycle: 0
~etc etc
DPMS is disabled
~etc etc

Hi Ken,

Thanks for the input. Mine is different from yours in that I have: prefer blanking: yes, allow exposures: yes. Also I have DPMS enabled. How do you turn those off?

Okay, I think I have found good directions here:
idratherhack.blogspot.com/2011/09/disabl...n-linux-how.html?m=1

However, I still get the RTAPI: Error: Unexpected real time delay on task 1 whenever I open LCNC.

Any other ideas?

Thanks,

Mr. Technical

Post the dmesg after you get the error to see
how bad the timing really is

Its better if you trim the log before posting by clearing dmesg first:

sudo dmesg -c
(run linuxcnc)
dmesg > log.txt

and post log.txt here

If you still have crazy elapsed times between servo threads and
you _have_ disabled all power management in the BIOS.
I would say the either that motherboard is not suited to real time use
(perhaps because its BIOS wont let you change power management settings)
or that there is a hardware issue of some kind.
A bad/failing hard drive can cause this kind of behavior for example

I have turned off all of the power management junk in the BIOS except for the ACPI function. If I turn that off, it won't even open Wheezy. Here's the file that dmesg output. Thanks for taking a look.

Mr. Technical

Notice the CPU frequency shows as 3.4 GHz:
127.987593] SYSINFO: CPUs 2, LINUX APIC IRQ 2312, TIM_FREQ 12499068, CLK_FREQ 3400005000, CPU_FREQ 3400005000



[ 128.275004] In recent history there were
[ 128.275005] 27192739, 230997499, 24341568, 403996, and 16254574
[ 128.275006] elapsed clocks between calls to the motion controller.
[ 128.275008] This time, there were 27188759 which is so anomalously
[ 128.275009] large that it probably signifies a problem with your
[ 128.275010] realtime configuration. For the rest of this run of
[ 128.275010] EMC, this message will be suppressed.

again these numbers are crazy

assuming you have a 1 ms servo thread period, these numbers (which are in CPU clocks)
should all be close (say within 5%) to 3,400,000 (or 2,800,000 if your CPU frequency is really 2.8 GHz)

Instead of regular 1 ms periods the numbers above represent servo thread times of about

9.7 ms
82.5 ms
8.7 ms
144 us
5.8 ms

Assuming nothing is really broken in your installation, it really looks
like real time is not working at all on your motherboard
at this point I would give that motherboard a decent retirement job
that does not involve running LinuxCNC

Thanks, I'll take your advice. It's a shame; this was purchased specifically for this retrofit, but at least I can move on to plan B now.

Mr. Technical

Well depending on how much you want to fuss with it, you could try a earlier or later version of the underlying OS

Whats OS are you using? (the latest Linuxcnc ISO is wheezy + RTAI 3.4.9 I believe)
If you have these results with Wheezy you might try the earlier Ubuntu 10.04 + RTAI 2.6.something
(or vice versa)

If you really want to get exotic you might try a different kernel and Preemt-RT

I too suffered similar problem with the real time thingy, it keep coming back. even went into .conf defaults.conf etc etc files but Finally got it switched off by writing a simple .sh file, make it executable and add it to the startup application list.
I get my jitter down to ~20-ish from 26-ish with my no frill atom d2500 after I switched off the dmps, screensaver and