High latency numbers on Intel D945PVS motherboard

Hi All,

I'm having trouble reducing the latency on my computer. I get readings up to 345000ns of jitter on the base thread and 650000ns on the servo thread.
The numbers typicaly jumps up to these values when starting firefox.


I have a Intel D945PVS motherboard. It's equipped with a Intel Pentium running at 3.00GHz and 2GB of RAM.

This is what I've done in the BIOS-settings.in order to reduce the latency:

• SW Single prosessor mode: Enabled
• MAX CPUID Value enabled
• On board Audio disabled
• ASF Support Disabled
• ACPI Suspend state set to "S1 State"

I've disabled any powersaving settings in the systems menu.

My best guess is that both kernels are still running. But I'm not sure how to turn one of them off.:

Any hints?

Cheers!
Bernie

This may also be video board related so you might try another video board

andypugh wrote:

Rather than run uniprocessor you might want to use isolcpus to let RTAI have a whole CPU to itself.

wiki.linuxcnc.org/cgi-bin/wiki.pl?TroubleShooting

And especially:

wiki.linuxcnc.org/cgi-bin/wiki.pl?The_Is..._Parameter_And_GRUB2

Thanks for the links.

Tested both solcpus=0 and isolcpus=1, but there is no improvment. isolcpus=0 on uniprocessor gave a nice kernel panic.

I will have a look at my videocard next.


Cheers!
Bernie

Hi!

Replaced the Nvidia driver with the Nouveau driver did the trick.

These are the numbers I'm getting now:

Servo Thread (1 ms)Max interval: 998760, Max jitter: 3600
Base Thread (25 us) Max Interval: 29405, Max jitter: 4526

Hardware info:
Motherboard: Intel D945PVS
CPU: Intel Pentium D 3.00 GHz
RAM: 2GB (667MHz)
GFX: Nvidia GForce 7300GS running on Nouveau (Version 20091212 ??)
GRUB settings: isolcpus=1
Running software while testing: glxgears, Firefox, desktop remotely controlled, copying files, etc. for 1 hour.

And I have turnend off the single prossessor mode in BIOS again.

Thanks for the prompt help!
Bernie