QTplasmaC upgrade now huge latency

I ended up buying it because it was $103 and had a SSD as well.

I isolated the cores today and ran the test. Still need to do the kernel upgrade.  

That is OK for a Mesa card and about where mine ran for years. I'll try and remember to look at my brix tonight.
Did you do the cpu affinity?

Not OK, notice the red/blue vertical lines on both sides of the histogram, those are excursions outside the visible area that do not show unless explicitly requested, so
latency-histogram --nobase --sbinsize 1000 --show
will show those excursions.
Although it just might be usable for Mesa, but i would not risk it.

I went through the google dock and enlisted the help of ChatGPT and this is what I did and the results.

• CPU: Intel Celeron J1900 @ 1.99GHz (4 cores)
• Kernel: 6.3.0-rt11-linuxcnc (upgraded from 6.1.0)
• NIC: Realtek RTL8111/8168/8411 (using r8168-dkms driver 8.051.02)
• Power Supply: Switched to a more stable supply from the plasma table

What I Did:

1. Installed the 6.3.0-rt11-linuxcnc kernel.
2. Installed and configured the r8168-dkms driver.
3. Disabled EEE on the NIC (r8168.EEE=0).
4. Set kernel boot parameters:

isolcpus=1,2,3 nohz_full=1,2,3 rcu_nocbs=1,2,3 pcidle.max_cstate=1 processor.max_cstate=1 idle=poll


5. Assigned IRQ 91 (NIC) to CPU core 1.
6. Set all CPUs to performance governor (persistent in rc.local).
7. Confirmed BIOS settings: C-states disabled, Turbo Boost off, EIST off.

 

In BIOS hyperthreading must be disabled, and TPM also.
And in case you find "aggressive link management" regarding PCI-E, also disable.