Installing LinuxCNC 2.9 or Master on Linux Mint 21

Post your config. And hardware. I was chasing latency past week.

Stanislavz wrote:

Post your config. And hardware. I was chasing latency past week.

Do you mean the linuxcnc configuration and the hardware of my pc?

Both. Especially grub parameters. And some screnshots from htop and watch cat /proc/interrups while making tests.

So.. j3355 with Mint in its place. All runs nice and smooth.

Stanislavz wrote:

Both. Especially grub parameters. And some screnshots from htop and watch cat /proc/interrups while making tests.
 

PC:
Motheboard gygabyte ga h61m s2pv
Ram 4gb (shared with dedicated graphics) 

The other information you can see in the screenshot.

The same thing happens to me with the debian booster with the RT kernel.
In booster with RTAI I have a latency of 10-15k at full
 

Ok. Change grub line to : nomodeset isolcpus=nohz,domain,1 apparmor=0

Install i7z and run it also. Run it first to note cpu frequency and voltage.

Use command latency-histogram --nobase --servo 50000

In htop - add cpu column and sort by it desc

Stanislavz wrote:

Ok. Change grub line to : nomodeset isolcpus=nohz,domain,1 apparmor=0

Install i7z and run it also. Run it first to note cpu frequency and voltage.

Use command latency-histogram --nobase --servo 50000

In htop - add cpu column and sort by it desc
 

I leave you here the captures.

The screen resolution has changed after changing grub and I can't change it.

Resolution is changed due to nomodeset command. You may try without it.

From graph - much of the noise have gone. Try to run also just latancy-histogram as usual.

And 10 glxgears is too much. 2 + youtube is ok. Pc have to loaded comfortably till 100, and with varying load. This would like to have 7 more time of cpu power to use.

Stanislavz wrote:

Resolution is changed due to nomodeset command. You may try without it.

From graph - much of the noise have gone. Try to run also just latancy-histogram as usual.

And 10 glxgears is too much. 2 + youtube is ok. Pc have to loaded comfortably till 100, and with varying load. This would like to have 7 more time of cpu power to use.
 

I understand.

with rtai kernel i think that on my pc i could reduce the latency even by half.

Do you think it can be made to work on linux mint?

I do no know. As far as i see it all rtai / vs preemt_rt - rtai is less stable and is used as last resort for system if you cant make good latency figures from preemt_rt.

Ok. I am an developer + part time unix admin. And my final thesis of master degree was on robust latency in multhireaded embedded systems.

Rtai runs two kernels in place of 1. On isolated core of corse.
Preemt run one process on isolated core too.
So - add one more kernel to rtai and we are on same level as f35...

And normal aproach is to remove all "noise" from isolated core and run only one process on it.

But yes - i think i will try rtai too. Just need some spare time. Still transfer to j3355 and mint was unplanned...

And this all was for one bigger stirling engine project. Second iteration now.