Welcome to LinuxCNC.org

Hey all,

Here are my computer's specs

AMD Althon XP 3000+
512 mb of DDR333 (2x256 modules)
Asus a7v8x motherboard
nVidia Geforce 4 ti 4600
Quantum Fireball harddrive from an iMac

I can run 10.04 and 8.04 from the live cd with sub 15k latency jitter consistently.

When installed to my harddrive, the numbers are lower, but spike when I open a program that has not been launched since startup (not in cache?). It spikes to about 8ms. This problem doesn't exist when running from the LiveCDs.

Anyone have any thoughts? I have 8.04 installed on my HDD at this point in time.

My guess is with only 512Kb of memory it is swapping to the hard drive and that would be very slow indeed.

Can you check your memory usage and swap history in System > Administration > System Monitor while you open the file?

John

Hi John,

thanks for the reply. Zero swap is being utilized, although I did make the swap partition 1.2gb just for laughs.

I think you made a typo when you said 512 Kb. I was under the impression that 512 mb was more than enough for linuxcnc under 10.04 or 8.04

Edit: only 30% of memory is being used with linuxcnc 2.5 running under 8.04 off my HDD

Thanks,
Luke

Yea, I meant 512Mb and it was a SWAG until someone else like ArcEye comes along with a much better guess...

Do you get the spike if you run a non OpenGL GUI like TKlinux?

John

Not a problem at all John, any help or ideas are welcome.

I'm not sure what tklinux is, and when I try to run it from bash prompt it says 'command not found' so I'm not sure where to go with this one.

Although I would stress that the spike ONLY happens on first launch after a fresh start up.

Example: post fresh start up, I launch firefox. BOOM! 8ms jitter for a split second, then back to normal. Close firefox, and open it again, no increase in jitter.

It's only when a program is first started

If you fire up LinuxCNC from the menu it is one of the sim configs, I forget the exact name.

John