Unexpected realtime delay on task 0 on a HP8300

This started after updating to debian bookworm(12) I started getting these errors - can take a week or two of uptime.

First question - it task 0 the Linux task number or something from linuxCNC?

I've seen conflicting advise about kernel command line settings:

PCW wrote:
"Unless you have an actual latency issue I would not use any isolcpus
options at all"

vs linuxcnc.org/docs/html/install/latency-test.html

Not sure I really have a latency issue - could be some cron-job of systemd-timer job is getting fired off.

Right now I've turned off a couple of apt-timer jobs in systemd - need to wait for an error.
 

1. What is you servo thread period?
2. Do you have AMT disabled in the BIOS?
3. Do you have IRQ coalescing disabled? (man hm2_eth)
 

@PCW

1-  in ~/linuxcnc/configs/machine.ini  I have
SERVO_PERIOD = 1000000

2 - grub command line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet text isolcpus=2,3 apparmor=0 apm=off"

3 - I have in /etc/network/interfaces a line commented out
# hardware−irq−coalesce−rx−usecs 0

What ever is happening is rare - never happened while the machine was cutting. 

# hardware−irq−coalesce−rx−usecs 0
 
This should not be commented out

AMT is something that must be disabled in the BIOS,
not something that can be changed in the kernel/grub

I left things running overnight - got the same error - no time stamp<grump>.  (Is there a way to get a timestamp?).

Who or what is task-0 in the context of this error?

Trying enabling  hardware−irq−coalesce−rx−usecs 0

/etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eno1
allow-hotplug eno1
iface eno1 inet dhcp

#linuxCNC mesa interface
auto enp2s0
iface enp2s0 inet static
    address 192.168.10.1/24
    hardware−irq−coalesce−rx−usecs 0

,.,.
The mesa interface has a r8168 driver..

root@cnc:~# lspci |grep Ether
00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (Lewisville) (rev 04)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)





,.,.
BIOS settings:

I do have AMT off
  I also have all the power saving stuff turned off.

I do have:
Turbo mode - enabled
multi-processor - enabled
,.,.

I found this in dmesg - I was thinking that the stock r8168 works now with bookworm? Do I still need to build a special one?

r8168: loading out-of-tree module taints kernel.
[    1.396296] r8168: module verification failed: signature and/or required key missing - tainting kernel
[    1.419277] ACPI Warning: SystemIO range 0x0000000000000428-0x000000000000042F conflicts with OpRegion 0x0000000000000400-0x000000000000047F (\PMIO) (20220331/utaddress-204)
[    1.419282] ACPI: OSL: Resource conflict; ACPI support missing from driver?
[    1.419285] ACPI Warning: SystemIO range 0x0000000000000540-0x000000000000054F conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20220331/utaddress-204)
[    1.419287] ACPI: OSL: Resource conflict; ACPI support missing from driver?
[    1.419287] ACPI Warning: SystemIO range 0x0000000000000530-0x000000000000053F conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20220331/utaddress-204)
[    1.419289] ACPI: OSL: Resource conflict; ACPI support missing from driver?
[    1.419290] ACPI Warning: SystemIO range 0x0000000000000500-0x000000000000052F conflicts with OpRegion 0x0000000000000500-0x0000000000000563 (\GPIO) (20220331/utaddress-204)
[    1.419292] ACPI: OSL: Resource conflict; ACPI support missing from driver?
[    1.419292] lpc_ich: Resource conflict(s) found affecting gpio_ich

,.,.
Latency test is showing after 10-min:
max servo jitter of 12104ns
max base thread of 7557ns

,.,.
A bit OT:
Just checked - coreboot does not support the HP8300..
There was a industrial intel board that we used for digital-video back in the '90s that I know didn't have any hiccups other than thermal throttling of the MMU - which could be cured with the right heat-sink.  Wish I still had one..  
Such throttling still happens - some is independent of the management engines in the BIOSes  ..  Removing the thermal pads that go bad after a couple of years and replacing with good and proper heat-sink compound solves most of those problems.  Video apps put a LOT of load on the MMUs - had to add the right heat-sink and fan. 


 

Do you have an add-in Ethernet card?
because the built in Ethernet MAC on
a HP8300 is an Intel device not a Realtek
(at least the ones I have all have Intel MACs)

@PCW
Was editing my comment while you replied.

Turbo mode should be off

Do you have an add-on network card?

@PCW who wrote "Do you have an add-on network card?"

Yes - The mesa interface is a realtek RTL8111/8168/8411 running via r8168 driver,

The onboard intel runs the LAN .

No error for 24hrs - restarting with turbo off.