Latency Test not opening 10.04
31 May 2011 14:19 #10224
by centaur
Replied by centaur on topic Re:Latency Test not opening 10.04
Thanks PCW - If I find a copy of the U8.04 live CD and install it, can I easily identify which files are only EMC2 related when I run the update manager? I am assuming that if I just let the update manager run wild it will install stuff which may be counterproductive. Please excuse my ignorance - I have noticed that there are many files with names which are cryptic to me.
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31 May 2011 14:57 #10225
by PCW
Replied by PCW on topic Re:Latency Test not opening 10.04
8.04 is on the live CD download page. There are instructions on the wiki for updating the 8/04s live CD to the latest EMC (well they may e a bit out of date)
But you could check if your latency improves without updating anything, just running the latency test on 8.04. If it has a big improvement, it may be worth updating 8.04s EMC version to 2.4.6
But you could check if your latency improves without updating anything, just running the latency test on 8.04. If it has a big improvement, it may be worth updating 8.04s EMC version to 2.4.6
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31 May 2011 17:51 - 31 May 2011 17:55 #10228
by centaur
Replied by centaur on topic Re:Latency Test not opening 10.04
Hi PCW - I downloaded U8.04 live CD but not yet installed. While it was downloading I tried some things with the present U10.04 install and the MSI mobo. Something interesting happened. If I booted up with a USB flash drive plugged in, the system recognized the flash and produced some really low jitter numbers as follows: base= 6743; servo= 6283
Booting w/o the flash yielded much higher values. I repeated this a couple of time to make certain the values were not a fluke.
If all this is indeed OK I will just run with the USB flash plugged in. This will also allow me to load CNC programs into EMC2 which is why I wanted USB flash capability in the first place.
Another question: I have read what there is on the latency test in the docs but I am still unclear of the significance of the numbers that the test reveals. Partly from the above the values are:
servo: interval= 1001443 jitter= 6283
base: interval= 31256 jitter= 6743
I am gathering that the really important value is jitter. What does the 'interval' indicate and how important is this?
Thanks again!
BTW - per your suggestion I looked at the information regarding improving latency and for me it is really cryptic - hope I don't have to get into it.
Booting w/o the flash yielded much higher values. I repeated this a couple of time to make certain the values were not a fluke.
If all this is indeed OK I will just run with the USB flash plugged in. This will also allow me to load CNC programs into EMC2 which is why I wanted USB flash capability in the first place.
Another question: I have read what there is on the latency test in the docs but I am still unclear of the significance of the numbers that the test reveals. Partly from the above the values are:
servo: interval= 1001443 jitter= 6283
base: interval= 31256 jitter= 6743
I am gathering that the really important value is jitter. What does the 'interval' indicate and how important is this?
Thanks again!
BTW - per your suggestion I looked at the information regarding improving latency and for me it is really cryptic - hope I don't have to get into it.
Last edit: 31 May 2011 17:55 by centaur.
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01 Jun 2011 10:19 #10234
by Rick G
Replied by Rick G on topic Re:Latency Test not opening 10.04
Near the bottom of the Live CD download page...
"Ubuntu 8.04 Hardy Heron (older)
If you require an older version of Ubuntu, you can download Ubuntu 8.04. The CD image below has the old emc 2.3.x on it, but can be upgraded to 2.4.x by following instructions on our wiki.
•download the ISO (EU mirror) and burn it to a CD. (The MD5SUM of the CD is 1bab052ec879f941628927c988863f14"
You can just create the Live CD, boot from it and run the latency test from the CD before installing to see if you get an improvement.
Rick G
"Ubuntu 8.04 Hardy Heron (older)
If you require an older version of Ubuntu, you can download Ubuntu 8.04. The CD image below has the old emc 2.3.x on it, but can be upgraded to 2.4.x by following instructions on our wiki.
•download the ISO (EU mirror) and burn it to a CD. (The MD5SUM of the CD is 1bab052ec879f941628927c988863f14"
You can just create the Live CD, boot from it and run the latency test from the CD before installing to see if you get an improvement.
Rick G
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01 Jun 2011 14:47 #10237
by centaur
Replied by centaur on topic Re:Latency Test not opening 10.04
Hi Rick G - thanks for the info. You may not have noticed my latest post just above yours. With the conditions outlined I am getting fairly respectable jitter values. If I can get away with leaving a flash drive plugged in, that's OK with me. What do you think?
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01 Jun 2011 16:50 #10238
by centaur
Replied by centaur on topic Re:Latency Test not opening 10.04
Hi again - latest happenings with the latency issue:
I tried U8.04 live CD on the same computer and ran the latency test - very good jitter values - all sub 10,000! Also the USB port was recognized and mounted a flash w/o problems. Per your suggestions I am going to install U8.04/EMC2 build and try the upgrade of EMC2 per the Wiki.
I tried U8.04 live CD on the same computer and ran the latency test - very good jitter values - all sub 10,000! Also the USB port was recognized and mounted a flash w/o problems. Per your suggestions I am going to install U8.04/EMC2 build and try the upgrade of EMC2 per the Wiki.
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