ubuntu10.04 Lcnc 2.7 rtai error

Hello at all,

I've a issue whit mesa card and ubntu 10.04, at last I've see that the proble is on wheezy too .... if use italian language you have some problem (ubuntu pncconf not work properly and debian istallation fail!! .... if you set english alll works fine).

For my motherboard (asrock mini-itx ad2550b) the better choice is ubuntu (latency test 2 time better) but in debian and in ubuntu have a realtime error unexpected. I use from 2 year these motherboar for making machine (Lcnc 2.5 and 2.6) and I never see these.

Loking trought syslog file now I see that Lcnc have 2.6.3 32 rtai version .... but synaptic show 2.7.1 ???? Is norma?

iN BIOS i'VE DISABLE EVERYTHINGS .... but these realtime error sometime show up.

I've clear syslog file, reboot pc and Lcnc .... copy it and you can see on attach ...

everyone see in it somethings that not works?? (I see the realtime error at the end of file ...this things I can see by me ) ... but no others..



....news ... thie error appear at the start of Lcnc ar after some minute .... but not at every start of Lcnc ... sometime not show it... (I lauch Lcnc with terminal).


Regards
giorgio

ok I try this solution ..... in bios I've not disable ethernet ..... I hope someone can read the first part of syslog and send me a feedback ...

these row :

Oct 23 12:11:52 k1-desktop kernel: [ 0.000000] AMI BIOS detected: BIOS may corrupt low RAM, working around it.

I not understand if is caused by me, when disabling all option in bios or is an advertising about my rtai problem.

The second I read abaut ACPI can cause rtai problem .... and ACPI control fun speed for example but in bioos I've disable it for example (is a fanless motherboard).....

You appear to be using a Mesa board, so presumably only have a servo thread?

What is your latency-test result?

As Andy has said, there can quite often be a big spike when everything loads, which is never repeated and causes no further problem.

Do the rtai latency test as described in my FAQ

www.linuxcnc.org/index.php/english/forum...me-latency-solutions

and you will be able to see if the spikes relate to file loading, graphics rendering etc and if they are repeated or just one offs.

You can try isolating cores too if you wish, but with a FGPA card you don't need to get hung up on it.
Debian is a bit of a 'heavier' system and the 3.4.9 kernel does not tend to produce as good results as the 3.6.32-122 one did
but you can run a 5i25 quite happily with a notional 50K + jitter

regards

the error is correlated with open and close windows ..... is 40min that run Lcnc ... no error appear .... I open firefox for post and the error appera .... motion.servos.overruns not increment .....

this monitor is for see if realtime error causes some problem to motion??

@ arcEyes These internal grphic card can causes problem ....

00:02.0 VGA compatible controller: Intel Corporation Device 0be2 (rev 0b)
Subsystem: ASRock Incorporation Device 0be2
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 11
Region 0: Memory at dfc00000 (32-bit, non-prefetchable) [size=1M]
Region 1: I/O ports at f0f0
Capabilities: <access denied>

00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: 0000e000-0000efff
Memory behind bridge: dfe00000-dfefffff
Prefetchable memory behind bridge: 00000000d0000000-00000000d01fffff
Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B-
PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
Capabilities: <access denied>
Kernel driver in use: pcieport
Kernel modules: shpchp

correspond to ICH7_1 ??

correspond to ICH7_1 ??

No, you have ICH7_2, the _N bit is the rev number

00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02)

In my experience the Atom MBs from D945GCLF through the D2800s have quite bad latency
Their latency test results are generally good but if you physically measure
latency by say toggling a parallel port pin you will find that they have 50 to 75 usec latency
_when they actually do something_ The latency test _doesn't do anything_ so only tests
dispatch latency.

Dispatch latency very optimistic compared to actual latency when memory allocation and physical I/O need to be done

If you want an education in whats going on, try plotting (with halscope) some of the hal function times
(watch the plot as you open firefox or move the mouse)


If you get a RTAI error on a 1 KHz thread that means you have at least a 200 usec variation from thread to thread
(The warning happens when the error is more than 20% of the thread time IICRC)


I dont have and real time errors on my D510 running an identical setup so something must be different
The D2550 does have different video than the D510 which might be an issue
(and uses the poorly supported Power VR hardware)

@ ArkEyes ... than not have SMI problem?

... actually running latency test on these pc from 4 hour.... (videos and other ...) 20000 1msec - 23000 25usec

@PCW I'm no expert but I was pretty sure of the real world measurement ( with the parallel port to work for example ) was different that the measure only software ... I use the integrated video interface ....

If you want an education in whats going on, try plotting (with halscope) some of the hal function times (watch the plot as you open firefox or move the mouse)

Sorry I just do it .... I grab hm2_5i25.encoder.05.input-a 4000 sample at 1Khz trigger auto .... if there was a problem, what should I do ? I see only the signal that stay at 1 if don't move the jog-wheel ....

@ ArkEyes ... than not have SMI problem?

No, only the rev 1 chipset is noted to have SMI problem

... actually running latency test on these pc from 4 hour.... (videos and other ...) 20000 1msec - 23000 25usec

The figure for the 25us thread is irrelevant, because you will not be using a base-thread, 20K is perfectly acceptable for the servo-thread.

If you really want to scramble your brains run the latency test with arguments

latency-test 1ms
will run a latency test with just a servo thread, which is what you will actually have.

I have found in testing, that this often produces far worse results, especially on rt-preempt kernels for some reason, than running a latency test with 2 threads, even if one will not be used.

So much so in fact, that I am now running my mill with a dummy base-thread, which is not connected to anything, even though I have a 5i25 / 7i76 combo and only use the servo-thread.
It certainly produces no problems and I am trying to compare that config to a standard one, via an inline latency test I have written, to see if it is actually beneficial in real world machines.
Lot more testing to do.

regards