On 9/18/26 04:59, John Dammeyer wrote:
See below.
-----Original Message-----
From: Peter Wallace [mailto:[email protected]]
Sent: September 17, 2026 3:13 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Ethernet send packets jitter
On Thu, 17 Sep 2026, John Dammeyer wrote:
I wonder if I'm having the same problem.
I have a MESA 7i92H on a PC. I boot, I home all axis. Maybe jog around
a
bit. Then hit the ESTOP to remove power to the drives, turn off monitor
and
leave the shop. The PC stays running. A day or two later I come back and
everything is fine.
Or...
I get this message as shown in the attached latency.txt file.
Unexpected realtime delay on task 0 with period 1000000
This Message will only display once per session.
Run the Latency Test and resolve before continuing.
This error may not show up for days and never really when I'm working
with the system either running G-code or doing something manually.
If you have a Intel Ethernet chip on your PC do you have irq coalescing
disabled?
-----------------------------------------------------
Here's what google says I have:
AI Overview
The Lenovo ThinkCentre M57 (Type 9181) is an older business desktop computer
released around 2007 or 2008.
Overview and Specifications
Product Line: ThinkCentre M57 Small or Tower DesktopType Number: 9181
Original Processor: Typically came with Intel Core 2 Duo processors (such
as the E6540 or E6550) or Celeron options.
Memory: Originally shipped with DDR2 RAM (often 1 GB or upgradeable).
The Lenovo ThinkCentre M57 (9181-A1U) is equipped with an integrated Intel
82566DM Gigabit Ethernet Controller.
-----------------------------------------------------
The /etc/network/interfaces file does not have:
iface eth0 inet static
...
hardware-irq-coalesce-rx-usecs 0
It only has the MESA IP and mask.
Do you have isolcpus=N with N set to the last core in you grub file?
Which grub file? The .cfg created from the script?
If so do you also have the Ethernet IRQ pinned to the last core?.
Don't know how to do that.
I'm thinking maybe I should buy a newer PC and install LinuxCNC 2.9 and
leave 2.8 behind?
I've had good luck with older 7000 or 9000 series off lease Dells, with
2 to 4 core I5's, s/b available for $125 or less from the liquidators.
They are a bit of a power hog though. They help heat my garage.
If power draw is important, the pi clones run on 20 watts or less. An
RPI4 runs my Sheldon lathe, needs about 17 watts + monitor & does a fine
job.
Suggestions?
Thanks
John
Cheers, Gene
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