Guidance Needed! Initial LinuxCNC/PncConf setup

I ran the same latency test (latency-histogram --nobase --sbinsize 5000) as mentioned previously. I ran it for 52 minutes with 5 glxgears running, browser with about 20 tabs open.

 

You might want to try a different kernel to see if that helps or not. I have had issues with 5.10.xx-rt and upgraded to 6.0.0-rt.

sudo apt search linux-image*

I am on 6.0 (bullseye).

linux-image-6.0.0-0.deb11.6-rt-amd64/now 6.0.12-1~bpo11+1 amd64 [installed,local]

I ran:
sudo apt search linux-image*

Results:
 

I do not see a 6.0 but there is a 6.1.0-3. Which one would I install? And do I need to also install the headers or will they be installed with the kernel?

It has been a while since I installed my current kernel, what is the easiest way to install?

Then try 6.1.0.3

sudo apt install -y linux-image-6.1.0.3-rt-amd64 linux-headers-6.1.0.3-rt-amd linux-image-6.1.0.3-rt-amd64-dbg

I have updated the kernel and reran the tests. The latency test appears pretty much the same as above and the network latency test is right around the same as well.

So what does that mean? Is the biggest concern the network latency? Or do both look bad?

What can I do to fix this? Add a network card?

The network latency is the issue (if its still multiple ms)

You can try running the system with more relaxed timeouts
and see how you do. (set the WD timeout to say 10 ms and
the packet error limit to say 20)

Adding an Intel network card may help

It looks like this is a known problem with all kernels past 4.9. I have not read the links that Rod included in his post to see if there is any workaround or solution yet. It is late. Will read more tomorrow.

Network latency breaks Mesa ethernet connection #2281

Sray69 wrote:

It looks like this is a known problem with all kernels past 4.9. I have not read the links that Rod included in his post to see if there is any workaround or solution yet. It is late. Will read more tomorrow.

Network latency breaks Mesa ethernet connection #2281

I'm just a disciple studying under the grand master PCW !
This is whay I'm trying to get linuxcnc runnig on ARM hardware but its slow going.

In my experience the kernel network issues started past kernel 4.19.x.
The issue is quite hardware dependent and the 6.X kernels work acceptably
on most of my test machines (6.2 seems a bit better than 6.1)

What Ethernet hardware is on your motherboard?

Also your latency histogram shows only one core. why is that?
That will likely make your network latency worse...

PCW wrote:

In my experience the kernel network issues started past kernel 4.19.x.
The issue is quite hardware dependent and the 6.X kernels work acceptably
on most of my test machines (6.2 seems a bit better than 6.1)

What Ethernet hardware is on your motherboard?

Also your latency histogram shows only one core. why is that?
That will likely make your network latency worse...

It looks like the Ethernet hardware is as follows:
LAN Controller: Realtek RTL8111E
Ethernet Interface Type: Gigabit Ethernet

Yeah I noticed the single core on the histogram. I am not sure why it is only running one core. Any suggestions on how to fix that?