Fantastic latency on Live CD, horrible on HDD

Just wanted to post a quick update

Been running 2 instances of glxgears at different resolutions, 3 instances of "$ while true;do /bin/true;done", and 1 instance of "$ ping google.com"

So far running it for 2 hours straight

max jitter is 9257 ns / 9854 ns

max jitter is 9257 ns / 9854 ns

That is a pretty good loaded figure. About the same as my 2 workshop P4s which both run a 30K base thread rock solidly.

Can you post a copy of your xorg,conf file please so I can possibly use that as an example (better rename it xorg.conf.txt or similar or it won't upload).

I have a vanilla install of 10.04 on another partition, I will play with changing over to vesa driver on that and try to put together a simple method for creating the required xorg.conf.

I know already that telling people to interrupt the boot and go to a terminal session to use xorg-configure just freaks them, so will have to find an easier method for the Linux novice.

regards

Posting this from the LinuxCNC computer while the stress test is running. Reset the statistics for laughs an hour ago and I'm still 8.5k/8.5k

the only lines i added

Hi

Thanks for the file, now I have started looking into it, a couple of questions.

Is your monitor CRT or TFT/LCD etc?

How did you arrive at the refresh rates, do you have the manual or was that what xrandr threw up for that resolution?

regards

I know already that telling people to interrupt the boot and go to a terminal session to use xorg-configure just freaks them, so will have to find an easier method for the Linux novice.

It has been a while but I think I started here..

wiki.ubuntu.com/X/Config

This suggests that a simple solution would be to use gedit to create the file, save to proper location and then edit it to fit your needs.

also from my notes I downloaded a while ago...

In order to generate xorg.conf you need to switch to one virtual console using the key combination CTRL + ALT + F1.

Now execute the following commands:

# sudo service gdm stop
This command will stop the X.
Now we need to generate the xorg.conf file:
# sudo Xorg -configure
This has generated the file in ~/xorg.conf.new.
We need to make the X using it so we have to put this file inside /etc/X11/
# sudo mv ~/xorg.conf.new /etc/X11/xorg.conf
After moving this file to the proper location you can start the X again and see what happens:
# sudo service gdm start

Rick G

Hi Rick,

Thanks, that is pretty much all that is needed.

I couldn't find a simple Ubuntu wiki to link directly to, so will probably just use that
Telling people to interupt GRUB and edit the kernel params to force runlevel 3 etc. was never going to be a winner!

The Linuxcnc troubleshooting wiki pretty well covers things, except that it doesn't explain that you cannot use Xorg -configure when there is a running X server.
That has come up as a problem a few times on threads.

regards

ArcEye wrote:

Hi

Thanks for the file, now I have started looking into it, a couple of questions.

Is your monitor CRT or TFT/LCD etc?

How did you arrive at the refresh rates, do you have the manual or was that what xrandr threw up for that resolution?

regards

My monitor is an old LCD monitor. I found the user manual online and punched in the manufacturers range. VESA seemed to pick the best one for me and it worked. I hope it works as smoothly on other systems too.

Wiki now edited to incorporate both items

wiki.linuxcnc.org/cgi-bin/wiki.pl?Troubl...g#Using_Vesa_Drivers

excellent, glad my post could possibly help others in the future!

Really excited to get this thing hooked up to my stepper motors. Psyched that I finally got sub 10k latencies. Thanks again all for the help

Wiki now edited to incorporate both items

Looks good ArcEye, that should help a lot of people.

Rick G