ISO install of LinuxCNC on Debian 8 & Mint LMDE 2

RTAI kernel works better, now to get the latency down below 62. Stock Jessie Linuxcnc install on this machine is around 4 to 5 so this one will need a little work me thinks

Wowsa! Installed an old nvidia card into 64bit LMDE-2 and the latency dropped to 5.8. Jumps a little with glxgears etc but this machine is purely for CNC so really the only thing that will be running with be LCNC. Alot happier this time around!

Thanks for the update racedirector,

That might give me clues where to look.

I have not been able to get the latency down below 60-80 on my machine runnung debian 8.3 64bit on an intel j1800 based MB. I found and fixed a network driver error, PC-speaker driver error, adjusted bios settings, checked that the rt kernel was running, set to one core (isolcpus=1), all with little improvement. I have also started playing with smi but I don't think my answer lies there. Based on your experience I should try running headless next and see if that helps.

I have a drive configured with the stock Debian Wheezy linuxcnc distribution that gets 5 to 6 latency without stress and up to 14 while running 5xglxgears+pandora+youtube+package updates, all with the default bios settings and on-board video.

I did capture one error msg during the install of tjmarch's linuxcnc.iso.

Right at the start after answering yes to installing the RT kernel:

Do you want to install Rt-preempt Kernel (y/n)?
answer no to install sim mode
sed: can't read /etc/apt/sources.list.d/linuxcnc.list: No such file or directory
Executing: gpg --ignore-time-conflict --no-options --no-default- (...ETC)

I have scanned the rest of the command session and and it seems to go fine from there.

I will probably just stick with the official linuxcnc pre-build for now if it is video causing the problem. This MB has only pcie and mpcie and I don't have any compatible video cards plus the thin m-itx case I put it in has no room. I am really happy with it under wheezy straight out of the box and need to be spending this time finishing my machine.

Are you using software stepgen?

If not, you do not need to go down so low on latency. It seems everyone is trying to get such a very low latency that it distracts from the fact that unless you are using software stepgen you do not need to worry so much about latency, within reason of course. Also, from my research it seems that software stepgen is fairly stable with higher latency than you reported.

just my 2Cents

I'm around 15-30 if I use every method of reducing my latency, however my computer slows to a crawl. So i decided not to worry so much about latency of my PC. I'm pretty stable around 45-50 with occasional spikes, but I'm using MESA hardware and I'm not concerned with it.

Hello

Has anyone tried this using this install with an ethernet connection to a Mesa 7i76E card? I have an old Dell SFF Optiplex 745 with onboard Broadcom NIC, will this work or do I need a separate PCI card with a Realtek chip?

John

My experience with Broadcom is that they dont work well for real time YMMV