Asrock Q1900B-ITX

First post-be kind
Setup MB as above, 4MB of recommended Kingston value RAM in slot DDR3 A1. 60GB Kingston V300 SATA. Stuffed into a Mini-Box M350 case with a Mini-Box PicoPSU-90 for power. Debian Wheezy.

First test was without any changes and showed that the Wheezy install includes a screensaver which defaults to on and also a (separate) power saver which defaults to blanking the screen after~10 minutes. Switched those two guys to "off" and "never" and switched off onboard sound in the bios. Tests were run with 4 glx gears and (initially) with a youtube running and, after test number one a looping video played with VLC . Initial test timed at 20 minutes



test one: sound turned off(bios) screen saver and power saver off (Debian)

servo thread 25694
base thread 23786

test two no change testing new setup with looping video

servo thread 25184
base thread 20942

test three disabled enhanced halt state (C1E) in bios

servo thread 14904
base thread 20810

Now, where to from here? I know about Isolcpus but I would like to do some further work on bios first to see if I can get better numbers. Any suggestions?

Martin

drummond wrote: Now, where to from here?

Start building the system. Those latency numbers are OK.

Thanks, I did find another "howler" which needed some help.

Primary Graphics Adapter defaults to PCI express rather than onboard, since I'm not using a card for graphics I switched it back to onboard, so:

test four Primary Graphics Adapter switched to "onboard"

servo thread 13385
base thread 17999

i know this thread is a little old. But last week i bought an Q1900B-ITX, too and first i had the same jitters as you.
But some small changes wihtin your Bios setup will make this mainboard a very good and low cost linuxcnc controller.
My jitters are :
Servo Thread : 5831
Base Thread : 7492

Got to your Bios to:
Advanced --> CPU Config --> Disable everything beside "No-Execute Memory Protection
Then go to:
Advanced --> Super IO --> Device Mode --> Bi-Directional
and
--> Change Settings -> IO=378 with every IRQ

This should do a quite decent job. If you still want some more (which is not necessary) than you can switch off every power saving option and put every option wich has an "auto" in it to a fixed value. For example DRAM "auto" to 1.55 V .
The more fixed values, the better.

Interesting.
I have the same board with 8GB value ram and onboard graphic card. What Linux Version did you use and was it 64bit or 32bit Version.
My values depend on what kernel i use (rtai or preempt-rt) and (32bit / 64bit). Best case 10000 and worst case 100000 latency.

Isolcpus 1,2,3
gives in this board huge jitter improvement