Dell Optiplex GX280

Hello everybody,
I have tested a computer, a Dell Optiplex GX280 (pentium 4 3.0Ghz 1024Mb RAM, Intel chipset and integrated video board) with Ubuntu 8.04 + EMC2, using latency test tool it seem a good HW, the result is Max Jitter (25 us thread) < 20000, but when run EMC2 have an Unexpected realtime delay; check dmesg for details
I have made a test with halscope reading parport.0.read.time and the result are some spike of 130000...
I have just loaded the module rtai_smi, may depend by the integrated video card? there is a solution?
Have you any idea?

Thank you for answers
Bye
Dino

Hi

See wiki.linuxcnc.org/emcinfo.pl?TroubleShooting

for an overview of all the possible issues.

If you run a latency test in a terminal from /user/realtime-(kernelnumber)/testsuite/kern/latency/run it will give a scrolling display with timing.

SMI spikes are very periodic and are usually 32 secs or multiple thereof apart (64 has been seen) .
If I am reading the halscope properly, these spikes are about 70 milliseconds apart?

I don't think Dell (or at least some of the models) enjoy a good reputation when used with EMC, we don't see too many of them in the UK, I expect John or one of the US members can advise.

As a comparison, without meaning to sound smug, my P4 2.8gHz Fujitsu Siemens boxes return a steady 10500 latency on 8.04 without any changes (save turning off power monitoring etc in BIOS.)

regards

How long did you run the latency test? You need to run it for a while to see if there are problems.
It looks like you may need to try the SMI fix.
What did you find with dmesg?
What configuration file did you use, one of the samples or one you created with stepconfig that you applied your tested latency results. Some of the sample configs may be too fast for your computer until you fine tune it.

The link ArcEye pointed out has a lot of great info if you have not already start there.
After you check the SMI I would go on to try a different video driver.
As far as Dell goes three of my machines use Dell and work great, I will have to look but I think one of them needed the SMI fix.

Rick G

Thank you so much for answers.

Today have made some more tests:

======== by /usr/realtime-2.6.24-16-rtai/testsuite/kern/latency without SMI workaround:

RTH| lat min| ovl min| lat avg| lat max| ovl max| overruns
RTD| -1921| -1940| -741| 5818| 48591| 0
RTD| -1921| -1940| -868| 5885| 48591| 0
RTD| -1921| -1940| -666| 5860| 48591| 0
RTD| -1922| -1940| -775| 5811| 48591| 0
RTD| -1920| -1940| -879| 6116| 48591| 0
RTD| -1922| -1940| -795| 24370| 48591| 0
RTD| -1908| -1940| -893| 5945| 48591| 0
RTD| -1920| -1940| -807| 26699| 48591| 0
RTD| -1938| -1940| -610| 5894| 48591| 0
RTD| -1915| -1940| -880| 37659| 48591| 0
RTD| -1915| -1940| -808| 5922| 48591| 0
RTD| -1922| -1940| -857| 5876| 48591| 0
RTD| -1919| -1940| -634| 5838| 48591| 0
RTD| -1922| -1940| -553| 5870| 48591| 0
RTD| -1894| -1940| -873| 6652| 48591| 0
RTD| -1922| -1940| -140| 5893| 48591| 0
RTD| -1914| -1940| -891| 5874| 48591| 0
RTD| -1922| -1940| -385| 6187| 48591| 0
RTD| -1922| -1940| 371| 11761| 48591| 0
RTD| -1922| -1940| 24| 5762| 48591| 0
RTD| -1918| -1940| -841| 5939| 48591| 0
RTH| lat min| ovl min| lat avg| lat max| ovl max| overruns
RTD| -1922| -1940| -364| 37430| 48591| 0
RTD| -1836| -1940| -650| 5933| 48591| 0
RTD| -1922| -1940| -190| 5979| 48591| 0
RTD| -1922| -1940| -67| 5881| 48591| 0
RTD| -1922| -1940| -73| 6268| 48591| 0
RTD| -1922| -1940| 194| 5930| 48591| 0
RTD| -1922| -1940| -13| 6791| 48591| 0
RTD| -1922| -1940| 253| 6011| 48591| 0
RTD| -1922| -1940| -435| 6093| 48591| 0
RTD| -1865| -1940| -909| 6026| 48591| 0
RTD| -1865| -1940| -909| 6026| 48591| 0


real 42m10.235s
user 0m0.200s
sys 0m0.124s
root@emc2-dell:/usr/realtime-2.6.24-16-rtai/testsuite/kern/latency#

dmesg

[ 86.551603] I-pipe: Domain RTAI registered.
[ 86.551611] RTAI[hal]: <3.6.1> mounted over IPIPE-NOTHREADS 2.0-04.
[ 86.551614] RTAI[hal]: compiled with gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3).
[ 86.551620] RTAI[hal]: mounted (IPIPE-NOTHREADS, IMMEDIATE (INTERNAL IRQs DISPATCHED), ISOL_CPUS_MASK: 0).
[ 86.551622] PIPELINE layers:
[ 86.551625] f8b63000 9ac15d93 RTAI 200
[ 86.551627] c0383180 0 Linux 100
[ 86.647520] RTAI[malloc]: global heap size = 2097152 bytes, <BSD>.
[ 86.650573] RTAI[sched]: loaded (IMMEDIATE, UP, USER/KERNEL SPACE: <with RTAI OWN KTASKs>, kstacks pool size = 524288 bytes.
[ 86.650580] RTAI[sched]: hard timer type/freq = 8254-PIT/1193180(Hz); default timing: periodic; linear timed lists.
[ 86.650584] RTAI[sched]: Linux timer freq = 250 (Hz), CPU freq = 2992694000 hz.
[ 86.650587] RTAI[sched]: timer setup = 2010 ns, resched latency = 2688 ns.
[ 2615.081006]
[ 2615.081008]
[ 2615.081009] CPU USE SUMMARY
[ 2615.081013] # 0 -> 25296098
[ 2615.081015] END OF CPU USE SUMMARY
[ 2615.081016]
[ 2615.100629] SCHED releases registered named ALIEN RTGLBH
[ 2615.113184] RTAI[malloc]: unloaded.
[ 2615.212928] RTAI[sched]: unloaded (forced hard/soft/hard transitions: traps 0, syscalls 0).
[ 2615.218359] I-pipe: Domain RTAI unregistered.
[ 2615.218370] RTAI[hal]: unmounted.



======== by /usr/realtime-2.6.24-16-rtai/testsuite/kern/latency with rtai_smi.ko module inserted:

root@emc2-dell:/usr/realtime-2.6.24-16-rtai/testsuite/kern/latency# insmod /usr/realtime-2.6.24-16-rtai/modules/rtai_smi.ko

RTH| lat min| ovl min| lat avg| lat max| ovl max| overruns
RTD| -1690| -1940| -905| 5849| 39193| 0
RTD| -1819| -1940| -773| 5845| 39193| 0
RTD| -1439| -1940| -909| 5998| 39193| 0
RTD| -1633| -1940| -895| 5373| 39193| 0
RTD| -1835| -1940| -794| 5849| 39193| 0
RTD| -1664| -1940| -903| 5917| 39193| 0
RTD| -1576| -1940| -898| 5680| 39193| 0
RTD| -1459| -1940| -910| 5844| 39193| 0
RTD| -1514| -1940| -894| 5922| 39193| 0
RTD| -1831| -1940| -793| 5931| 39193| 0
RTD| -1570| -1940| -908| 6052| 39193| 0
RTD| -1936| -1940| -692| 5745| 39193| 0
RTD| -1545| -1940| -909| 5984| 39193| 0
RTD| -1793| -1940| -893| 5813| 39193| 0
RTD| -1808| -1940| -890| 9304| 39193| 0
RTD| -1887| -1940| -868| 5931| 39193| 0
RTD| -1922| -1940| -689| 5830| 39193| 0
RTD| -1921| -1940| -858| 37669| 39193| 0
RTD| -1936| -1940| -568| 38753| 39193| 0
RTD| -1841| -1940| -869| 5924| 39193| 0
RTD| -1922| -1940| -728| 6439| 39193| 0
RTH| lat min| ovl min| lat avg| lat max| ovl max| overruns
RTD| -1905| -1940| -787| 5897| 39193| 0
RTD| -1808| -1940| -900| 6010| 39193| 0
RTD| -1879| -1940| -885| 5925| 39193| 0
RTD| -1879| -1940| -885| 5925| 39193| 0


real 68m40.607s
user 0m0.192s
sys 0m0.176s
root@emc2-dell:/usr/realtime-2.6.24-16-rtai/testsuite/kern/latency#

dmesg

[ 2862.322532] RTAI: Intel chipset found, enabling SMI workaround.
[ 2862.322544] SMI configuration has been set, mask used = 1.
[ 2883.845984] I-pipe: Domain RTAI registered.
[ 2883.845992] RTAI[hal]: <3.6.1> mounted over IPIPE-NOTHREADS 2.0-04.
[ 2883.845994] RTAI[hal]: compiled with gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3).
[ 2883.846000] RTAI[hal]: mounted (IPIPE-NOTHREADS, IMMEDIATE (INTERNAL IRQs DISPATCHED), ISOL_CPUS_MASK: 0).
[ 2883.846003] PIPELINE layers:
[ 2883.846005] f8b63000 9ac15d93 RTAI 200
[ 2883.846007] c0383180 0 Linux 100
[ 2883.909155] RTAI[malloc]: global heap size = 2097152 bytes, <BSD>.
[ 2883.911750] RTAI[sched]: loaded (IMMEDIATE, UP, USER/KERNEL SPACE: <with RTAI OWN KTASKs>, kstacks pool size = 524288 bytes.
[ 2883.911758] RTAI[sched]: hard timer type/freq = 8254-PIT/1193180(Hz); default timing: periodic; linear timed lists.
[ 2883.911761] RTAI[sched]: Linux timer freq = 250 (Hz), CPU freq = 2992694000 hz.
[ 2883.911764] RTAI[sched]: timer setup = 2010 ns, resched latency = 2688 ns.
[ 7001.924962]
[ 7001.924964]
[ 7001.924965] CPU USE SUMMARY
[ 7001.924969] # 0 -> 41199699
[ 7001.924970] END OF CPU USE SUMMARY
[ 7001.924971]
[ 7001.942377] SCHED releases registered named ALIEN RTGLBH
[ 7001.958470] RTAI[malloc]: unloaded.
[ 7002.056881] RTAI[sched]: unloaded (forced hard/soft/hard transitions: traps 0, syscalls 0).
[ 7002.062274] I-pipe: Domain RTAI unregistered.
[ 7002.062284] RTAI[hal]: unmounted.



====== Using /usr/bin/latency-test with SMI workaround

root@emc2-dell:~# time /usr/bin/latency-test

real 105m23.340s
user 0m0.144s
sys 0m0.140s
root@emc2-dell:~#

Max interval(ns) MAX JITTER(ns) Last interval(ns)
Servo thread (1.0ms): 1008715 12334 996093
Base thread (25.0us): 44080 20318 24460

dmesg

[ 7194.600640] I-pipe: Domain RTAI registered.
[ 7194.600649] RTAI[hal]: <3.6.1> mounted over IPIPE-NOTHREADS 2.0-04.
[ 7194.600652] RTAI[hal]: compiled with gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3).
[ 7194.600657] RTAI[hal]: mounted (IPIPE-NOTHREADS, IMMEDIATE (INTERNAL IRQs DISPATCHED), ISOL_CPUS_MASK: 0).
[ 7194.600660] PIPELINE layers:
[ 7194.600662] f8b63000 9ac15d93 RTAI 200
[ 7194.600665] c0383180 0 Linux 100
[ 7194.615553] RTAI[malloc]: global heap size = 2097152 bytes, <BSD>.
[ 7194.617510] RTAI[sched]: loaded (IMMEDIATE, UP, USER/KERNEL SPACE: <with RTAI OWN KTASKs>, kstacks pool size = 524288 bytes.
[ 7194.617518] RTAI[sched]: hard timer type/freq = 8254-PIT/1193180(Hz); default timing: periodic; linear timed lists.
[ 7194.617521] RTAI[sched]: Linux timer freq = 250 (Hz), CPU freq = 2992694000 hz.
[ 7194.617523] RTAI[sched]: timer setup = 2010 ns, resched latency = 2688 ns.
[ 7194.636993] RTAI[math]: loaded.
[ 7194.641296] RTAI: Intel chipset found, enabling SMI workaround.
[ 7194.641309] SMI configuration has been set, mask used = 1.
[13514.260514] RTAI[math]: unloaded.
[13514.271628] SCHED releases registered named ALIEN RTGLBH
[13514.287542] RTAI[malloc]: unloaded.
[13514.387278] RTAI[sched]: unloaded (forced hard/soft/hard transitions: traps 0, syscalls 0).
[13514.389839] I-pipe: Domain RTAI unregistered.
[13514.389847] RTAI[hal]: unmounted.



==========

BUT when run emc2 with stepper/stepper_mm configuration have unexpected realtime delay

dmesg

[14033.520439] I-pipe: Domain RTAI registered.
[14033.520449] RTAI[hal]: <3.6.1> mounted over IPIPE-NOTHREADS 2.0-04.
[14033.520451] RTAI[hal]: compiled with gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3).
[14033.520457] RTAI[hal]: mounted (IPIPE-NOTHREADS, IMMEDIATE (INTERNAL IRQs DISPATCHED), ISOL_CPUS_MASK: 0).
[14033.520459] PIPELINE layers:
[14033.520462] f8b63000 9ac15d93 RTAI 200
[14033.520464] c0383180 0 Linux 100
[14033.533861] RTAI[malloc]: global heap size = 2097152 bytes, <BSD>.
[14033.534166] RTAI[sched]: loaded (IMMEDIATE, UP, USER/KERNEL SPACE: <with RTAI OWN KTASKs>, kstacks pool size = 524288 bytes.
[14033.534172] RTAI[sched]: hard timer type/freq = 8254-PIT/1193180(Hz); default timing: periodic; linear timed lists.
[14033.534175] RTAI[sched]: Linux timer freq = 250 (Hz), CPU freq = 2992694000 hz.
[14033.534178] RTAI[sched]: timer setup = 2010 ns, resched latency = 2688 ns.
[14033.608604] RTAI[math]: loaded.
[14033.618524] RTAI: Intel chipset found, enabling SMI workaround.
[14033.618537] SMI configuration has been set, mask used = 1.
[14033.734807] config string '0x0378'
[14056.209311] RTAPI: ERROR: Unexpected realtime delay on task 1
[14056.209314] This Message will only display once per session.
[14056.209316] Run the Latency Test and resolve before continuing.
[14157.247642] RTAI[math]: unloaded.
[14157.303764] SCHED releases registered named ALIEN RTGLBH
[14157.317764] RTAI[malloc]: unloaded.
[14157.417378] RTAI[sched]: unloaded (forced hard/soft/hard transitions: traps 0, syscalls 0).
[14157.419717] I-pipe: Domain RTAI unregistered.
[14157.419724] RTAI[hal]: unmounted.

==========================================================

Yesterday I have tested the PC with mine configuration, with
BASE_PERIOD = 37037
and
MAX_VELOCITY = 128.250

today have used a standard configuration with
BASE_PERIOD = 50000
and
MAX_VELOCITY = 30.48



i have noted that when the CPU fan increase or decrease velocity in halscope have a shot, someone know if it is possible set manually the fan velocity highest?

I have the possibility to change the pc with an other, always Dell Optiplex but GX270 not GX280, from wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Latency-Test it seem better then the PC I am using, someone know if it is really better?



Thanks

I believe one of the machines at work uses a GX2xx. I will look today and let you know what it is and the numbers.

I will also look in to the settings for that computer.

Have you tried a different video driver yet as shown in the troubleshooting section?

Take a look at the settings in your BIOS, is there anything there for fan control or power management, how about hyperthreading?

Just for the heck of it try turning your network card off in the bios.


Rick G

Thank you Rick G,
I have tried to change the video card with one in PCI bus but in BIOS there is no possibility to switch off the video card integrated, only "AUTO" and "ON BOARD" choice, in AUTO the output are displayed on both video cards, in ON BOARD only in on board of course, not tried yet to config linux kernel to use only one video card.

The BIOS of this PC have no possibility to set options for power-save, only AC-recovery, Auto power-on, suspend-mode and remote power on.
The Hiperthreading are disabled, but I think that have no importance becouse the kernel is compiled without multiporcessor features.

Tomorrow I will try to turn off network card (audio is turned off in BIOS) and configure kernel to use only the PCI video card.

Please check the code of your Dell for me!

Thanks!
Dino

Hello Dino,

Turns out mine is a GX260 and worked right out of the box without any changes.

I believe there was a post in the past about the cpu fan on some intel motherboards being a problem with Real Time, not sure if there was a solution.

But to back up a bit...

Ubuntu 8.04 + EMC2, using latency test tool it seem a good HW, the result is Max Jitter (25 us thread) < 20000,

Now if you run the latency test from the drop down menu for several minutes and maybe run glxgears from a terminal at the same time what results do you get? Take the result numbers if they are not too bad and run Stepconfig. Enter the results and Stepconfig will calculate how fast a thread you can run. Try running the config that stepconfig creates and see if there is a problem.

Couple of other thing to try.

Try booting from the 10.04 Live cd and run the latency test there. Might be better might be worse.

Try running the latency test with the cpu hog running.

wiki.linuxcnc.org/emcinfo.pl?RealTime

What video driver is selected in your xorg.conf file? Which have you tried? Any options set?

Rick G