Unexpected realtime delay on task 0 with period 1000000

Unfortunately its not trivial but there are instructions here

forum.linuxcnc.org/27-driver-boards/5366...xcnc?start=20#310794

I really think this should be fixed in the LinucCNC distribution as Realtek hardware is very common
and this affects all Ethernet connected LinuxCNC hardware.

The unfortunate thing is that this (massive Ethernet latency) was broken somewhere between
kernel revisions 4.x and 5.X and has never been fixed (the DKMS fix is a workaround, it should be fixed in
the stock Linux Kernel)
 

@PCW who would be the person group best suited to fixing it, and do they know about it? is this a linuxcnc thing or a debian thing?

OK, i hope it is done...

--- 10.10.10.10 ping statistics ---
54124 packets transmitted, 54124 received, 0% packet loss, time 54165ms
rtt min/avg/max/mdev = 0.050/0.109/2.531/0.048 ms

But the Error is still there...

Go to your Synaptic Package Manager.
Search (in my case) R8168-dkms
select and install package.
Reboot

There are several devices and other drivers for them. Search DKMS in package and look for the proper device.

2.531 is still way too large (even though its ~4x better)

Are all power saving option disabled in the BIOS? (Turbo modes,C state > C1 etc)

Other options are shown in the:

forum.linuxcnc.org/38-general-linuxcnc-q...nity?start=40#300434

thread

A simple thing to try is to run this script that sets the irq affinity

 

you first need to make the script executable with

chmod +x pinirq.txt

and then run it with:

sudo ./pinirq.txt  [ethernet_device_name]

Where [Ethernet_device_name] is something like eno1 or enp0s5
(the device name can be determined with the "ip a" command)

You can check that it worked with this script:

 

chmod +x checkmask.txt

and then run it with:

./checkmask.txt  [ethernet_device_name]

checkmask also shows the kernel command line

Lcvette wrote:

@PCW who would be the person group best suited to fixing it, and do they know about it? is this a linuxcnc thing or a debian thing?
 

Honestly its a Linux thing (broken driver) but would be easier to fix in a non debian compliant ISO
Ultimately it should get fixed in the kernel driver so the proprietary Realtek driver is not needed.

Latency related issue, so did you dissble all the power saving features in the BIOS?
Also disable hyperthrrading, TPM, turbo, etc.

PCW wrote:

Lcvette wrote:

@PCW who would be the person group best suited to fixing it, and do they know about it? is this a linuxcnc thing or a debian thing?
 
Honestly its a Linux thing (broken driver) but would be easier to fix in a non debian compliant ISO
Ultimately it should get fixed in the kernel driver so the proprietary Realtek driver is not needed.

Interesting, would it help the intel adapter performance as well? bring it back to the 4.9 kernel day performance?  i miss those days...lol

It's not a issue with Intel MACs
If you disable IRQ coalescing
and pin IRQs, You get pretty decent
performance.

For example on this HP8300 I have been running a test on a 7I76EU
with a 3 KHz servo thread for about 3 days while using the PC for general
web browsing, email etc and have not had any issues.
(CPU frequency is 2.9 GHz and times are in CPU clocks)