ubuntu 14.04.1 linuxcnc help

tjmarch wrote: I can see why you would want the pendent to teach robot arms with manual gcode entry which will be a tough way to go but I do not know of another way for robot path to be entered using linuxcnc.

A curious thing lives in the LinuxCNC code:
github.com/jepler/linuxcnc-mirror/blob/c.../scripts/teach-in.py

do you think installing a lighter system such as mint would improve latency? im not sure exactly where the bottleneck is in thiscomputer so limiting throughput may help?
Again i was wondering if anyone had reduced latency by increasing ram or cpu.
thanks
jason

I am sad to report back, i have tried linux mint 17 and despite the many latency reducing techniques i used with ubuntu, latency is very high on this os. I would have thought it would have been slightly better because of the lighter de. thats all for now

I have one old PC that had bad latency with Ubuntu 10.04, worse with Debian Wheezy and even worse with LinuxMint. I don't use that PC for real time anything.

JT

The way i got the latency down was by following the instructions here.
forum.linuxcnc.org/forum/18-computer/259...-pcs-success?start=6
I had the latency values down to `8000 and ~12000, but itried to reinstall ubuntu and follow these instructions to replicate it, but failed. i think i may have made a chang to the file titles? like add .sh? im not sure how these files change things at boot uo, but can someone confirm they are going to the right places? I was really excited to have had such good latency on a laptop, but i should have been documenting everything i was doing.

Razor_keen

I was thinking of using Rt-preempt 64 bit kernel myself latancy looked promising but so dose Rtai 32 bit install
been playing with both. I am also using a Intel dual core processor which was getting bad latancy spikes, the following procedures got rid of the spikes. The best latancy-test results I achieved were:

Latency Rtai kernel 32 bit system
needs to be re-reviewed

Latency Rt-preempt kernel 64 bit system
33273 us
33.273 ms

Also when adding idle=poll to what I show to add in todolist doubled latancy-test results for me

I have attached the files for you to view everything I did on 32bit and 64bit systems
Maybe something is listed that you have not tried, or you could try 32 bit install
When using Menu->CNC->LinuxCNC then Configuration Selector->apps->latency-plot
On 64 bit system I get a couple of spikes when latency-plot starts but after that it is stays low, accept when moving large folders full of files on hard drive:this has been resolved with edited todolist
Looks like I should not write to hard drive while machine will be running or check into a solid state drive: this has been resolved with edited todolist

Tim
Attached files edited 12/06/2015 11:55pm central