another 7i76e error finishing read question

Hi guys, I have an Intel i3 All in one touchscreen PC thats getting the dreaded "error finishing read" fault.
I'm wondering if there are any other things I can do to resolve this as the PC has decent overnight latency 
 

CPU: Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
RAM: 8 Gb
NIC: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
NIC Driver =  r8168  (I changed from r8169 default as I heard it could be buggy)
OS: Debian Bookworm:  SMP PREEMPT_RT Debian 5.18.16-1 (2022-08-10)
GUI: Default Debian GUI not XFCE
Ping times:
PING 10.10.10.10 (10.10.10.10) 56(84) bytes of data.
64 bytes from 10.10.10.10: icmp_seq=1 ttl=64 time=0.191 ms
64 bytes from 10.10.10.10: icmp_seq=2 ttl=64 time=0.103 ms
64 bytes from 10.10.10.10: icmp_seq=3 ttl=64 time=0.099 ms

isolcpus=2,3
Running QTPlasmac deb install compiled from source (V1.229.228)

So at this stage I am out of ideas.
Is Debian Bullseye any better?
Would XFCE help?
Any other ideas?
It seems a shame to give up on this PC as it has quite a good touch screen and more grunt than the usual Celeron J1900's I use

Can you post the results of

halcmd show param *.tmax

after LinuxCNC has run for a while?

Yeh, I did that. The 7i76e TMAX is up over 3000000.
I'll post it up this evening becasue the machine is at home.

Here are the tmax values. I did see a latency error this run while running halshow.
 <code>
debian@debian:~$ halcmd show param *.tmax*
Parameters:
Owner Type Dir Value Name
45 s32 RW 8088 db_arc-ok.tmax
45 bit RO FALSE db_arc-ok.tmax-increased
45 s32 RW 12236 db_breakaway.tmax
45 bit RO FALSE db_breakaway.tmax-increased
45 s32 RW 12252 db_float.tmax
45 bit RO FALSE db_float.tmax-increased
45 s32 RW 10168 db_ohmic.tmax
45 bit RO FALSE db_ohmic.tmax-increased
36 s32 RW 0 hm2_7i76e.0.read-request.tmax
36 bit RO FALSE hm2_7i76e.0.read-request.tmax-increased
36 s32 RW 5094432 hm2_7i76e.0.read.tmax
36 bit RO FALSE hm2_7i76e.0.read.tmax-increased
36 s32 RW 174540 hm2_7i76e.0.write.tmax
36 bit RO FALSE hm2_7i76e.0.write.tmax-increased
29 s32 RW 117656 motion-command-handler.tmax
29 bit RO FALSE motion-command-handler.tmax-increased
29 s32 RW 165036 motion-controller.tmax
29 bit RO FALSE motion-controller.tmax-increased
48 s32 RW 18992 ohmicsense.tmax
48 bit RO FALSE ohmicsense.tmax-increased
39 s32 RW 15032 pid.a.do-pid-calcs.tmax
39 bit RO FALSE pid.a.do-pid-calcs.tmax-increased
39 s32 RW 16656 pid.s.do-pid-calcs.tmax
39 bit RO FALSE pid.s.do-pid-calcs.tmax-increased
39 s32 RW 15540 pid.x.do-pid-calcs.tmax
39 bit RO FALSE pid.x.do-pid-calcs.tmax-increased
39 s32 RW 24784 pid.y.do-pid-calcs.tmax
39 bit RO FALSE pid.y.do-pid-calcs.tmax-increased
39 s32 RW 12792 pid.y2.do-pid-calcs.tmax
39 bit RO FALSE pid.y2.do-pid-calcs.tmax-increased
39 s32 RW 14732 pid.z.do-pid-calcs.tmax
39 bit RO FALSE pid.z.do-pid-calcs.tmax-increased
42 s32 RW 123728 plasmac.tmax
42 bit RO FALSE plasmac.tmax-increased
30 s32 RW 5145340 servo-thread.tmax
51 s32 RW 10472 stepboost.0.tmax
51 bit RO FALSE stepboost.0.tmax-increased
51 s32 RW 11044 stepboost.1.tmax
51 bit RO FALSE stepboost.1.tmax-increased
51 s32 RW 9476 stepboost.2.tmax
51 bit RO FALSE stepboost.2.tmax-increased
51 s32 RW 10220 stepboost.3.tmax
51 bit RO FALSE stepboost.3.tmax-increased
51 s32 RW 15500 stepboost.4.tmax
51 bit RO FALSE stepboost.4.tmax-increased
</code>

>>>>>36 s32 RW 5094432 hm2_7i76e.0.read.tmax

Yeah, 5094432/3.4G = ~1.5 ms,
so the Ethernet latency is definitely terrible.

Does the PC have an Intel MAC?

If so have you turned off IRQ coalescing?

The NIC is a Realtek RT8111 so not intel. I know somebody else who has trouble with this NIC and gave up on a similar machine.

I did try coalescing but it did not seem to make any difference so I took it out.

I might try on Bullseye instead of bookworm.

The Realtek driver does not support coalescing so its already "off"

I have used many motherboards with RT8111 MACs without latency issues
so I don't think the problem is the Realtek driver or the RT8111.

Are you sure you have all power management options disabled in the BIOS?

Many flat panel PCs are laptop like designs so have extensive power management
support.

PCW wrote:

Many flat panel PCs are laptop like designs so have extensive power management
support.

And few options to alter them
I will check the BIOS again but not much in there. I disabled all the power settings I could see.

But I see Reltek have a newer driver released in 2022. I might give it a go..
www.realtek.com/en/component/zoo/categor...pci-express-software

What does pinging the 7I76E show?

That was in my first post