Poor latency

Hi to all

This is not guaranteed solution, just an experience I want to share.

I made the same bad experience like others when switching an older pc from 8.04 to 10.04 …..

Reading a lot in www I came to tree points of suspect:
Motherboard communication (SMB), USB ( legacy support ) and Video.

I did it on the rude way and switched of:
1. all pc wakeups and especially all temperature and voltage control alarms
2. all USB legacy support for mouse and keyboard
3. video driver……. In my case NVIDIA. .... I'm still in phase of researching and testing.

As far as I can see the latency became better and especially stopped jumping to super high values.
(test time ca 5 minutes)

And yes I know CPU might burn up ….. but why in a cold cellar…. I can live with that risk.


Please, I hope to get "expiriences" from others if I'm dreaming or I'm on the right track

Mike

P.S.
I’m suspecting that older motherboard “interrupt drivers” are causing those long waits by some internal timeouts, or rude written wait cycles …

Andy just published this link at another thread:
wiki.linuxcnc.org/emcinfo.pl?FixingSMIIssues

Maybe when you installed 8.04 some years ago you disable SMI and forget it.
Then after upgrading to 10.04 its back again ?

It is a compley new installation from cd.. As I was not sucessfull via update
tried a lot including reformating, swap partition moved to a second disk, ...

Andys good text was one of the pages I studied in www.

Came accros the USB legacy support at some other cnc/ realtime related page, but can't remember where.

And I realy do not want to compile a special kernel, thats the wrong way if you want to be able to update..

If I only have to switch of the BIOS alarm support... I'll do it.

I just type a long message explaining my experience with the latency test and lost it due to automatic log out I think?
So this is a test!


OK, try again.

I am a new user of EMC and bought a "reconditioned" Dell Precision 390 with a dual core 2.1 Ghz and Nvidia Quattro video. I ran the new CD for 10.04 and everything went smooth. My latency test was a horrible 64 Usec servo and 25 Usec base. So I spent a day researching solutions. I decided the bios was the easiest so with a heavy hand I turned off everything I would not need on a dedicated machine controller. This included USB, NIC, Audio and others. I an NOT a PC expert so I just disabled anything I thought would be requesting an interrupt. When I rebooted with the new bios settings I got the same results as before. This was shocking but I decided it had to be the video card. I tried to force the vesa drivers from notes I found on the Wiki but failed. Then I pulled out the video card to record the model numbers with the intent of ordering a Matrox 450 PCI card. I replaced the original video card and rebooted. When I checked the latency again I was pleasantly surprised that numbers had fallen to <5 uSec servo and <3 uSec base. I think the Latency test has a problem reseting the peak test times as I had rebooted several times before and always saw the high numbers? I don't believe reseating the video card could make this difference as the video was fine before and after?

Back to the bad numbers and I did nothing. Rebooted several times and can't get the good numbers to return???

Hi Mick

As I read somewhere/understood some motherboard components want to communicate in "minutes interval" ...

And I could see that these enourmous latency values "apeared" repetitive after ca 1-2 minutes.

As pity, in the moment I'm time to do systematical researches.

Mike

Thanks John, I'm on a couple other forums that have the auto log off set short and I found if you click "remember me" you don't get zapped.

After a day banging away on the Latency test I have some interesting results:

When I first boot the computer and go to the Latency test I get 60+ uSec servo and 20+ uSec base.
I let it run for many minutes and hit reset a few times. It returns to the same numbers.

Now with the Latency test running I open the System>Admin>System Testing and select "Video" and run the 3D gears test; now hit reset on the Latency window and the numbers drop to 11+ uSec servo and 10+ base.
When I move the Gears window around the screen the numbers climb to 12+ on both.

Then I close the System test and hit reset on the Latency test window and the numbers fall to 2 uSec servo and 3 usec base. If I close and reopen the Latency window the numbers stay low. A reboot will bring back the high numbers.

I checked the "Hardware drivers and the report said that no Proprietary drivers are in use on this system.

The problem appears to be the initial mode of the video card that gets straightened out when the "gears" run??

Hello All -

Well, for starters I am level entry linux and emc but not machining.
But what I have found with is latency is interesting to say the least.
Well, maybe some one can find this info usefull.

Computer 1 -
MSI KM2M Combo mother board micro ATX,
Pro Savage DDR KM266 chip set
2.1 Athlon processor and 512 mem.
Tried to load iso Ver. Ubuntu 8.04 Hardy Heron but it did not like
the on board video Thusly went back and loaded Ubuntu 6.06 "Dapper Drake
and every thing worked just fine.
Latency test - WOW 1++ ms. tryed almost every thing,
from the bios to the os, nothing seemed to work.
Running a Gateway EV700 monitor

But on computer 2 - Compaq Peresario, SR1503WM
Celeron 2.9 processor, 512 men
Installed iso Ubuntu 8.04 Hardy Heron and every thing took but
latency was 1++ ms did every possiable and not much was gained,
then I put in a pci vid card and presto max latency was 25000us
with an occasional spike to 50000 after days of testing
It Worked ! Was running a Optiquest Z50.

So, I got the brain storm to put the monitor on that came with
the system back on, Mistake, latency went to 1++ ms
So, put the Optiquest Z50 back on and no improvment.

Then re loaded the os (8.04 Hardy Heron) with the Optiquest Z50
And every thing is good to go as before.

Ok, So, whats up with this ?
The monitor cauzed latency, could it be ? Very Interesting . . .
So maybe if I change the monitor on Copmuter 1, but
I have a feeling that it is the on board video.
Anyway, this system works for proofing out stuff and
will most likley have to be on the back burner.

B o b