Latency test - Servo thread or Base thread?

Hello all,

I am setting up a computer (Dell Optiplex GX620) for Linuxcnc to use on a lathe, I plan on using a cards from mesa and steppers in the set up. My latency numbers, after turning off hyperthreading, are coming back with a max jitter on the base thread of 25,000 and on the servo thread of 55,000. Do I just go with the larger number or the number from the base thread? Any suggestions for getting the latency numbers down?


Thanks,
Russell

When a hardware stepgenerator is used (as with Mesa or Pico Systems cards)
the base thread is not used at all so its jitter is not important.
55 uSec of jitter should be OK for a 1 mS servo thread

If you have a dual core processor you might try the isolcpus option to reduce latency:
wiki.linuxcnc.org/cgi-bin/wiki.pl?The_Is..._Parameter_And_GRUB2

Thanks for the response on this, it is a single core intel p4 so Isolcpus will not help. I also tried Ubuntu 8 but had even worse latency with that. I will push forward with what I have now and start ordering parts then.


Thanks