USB activity causes network error

I got this result when I ran the checkmask file. I am sure that I don't know how to use isolcpu. I want to isolate two cores with last core being 7.  SO cores 6 and 7 to be used for linuxcnc.

Cores: 8
Actual CPU Mask: ff
Desired CPU Mask: 128
IRQ: 24
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-40-rt-amd64 root=UUID=bfdcf9b0-7caa-4c4b-b4c3-585accea347a ro quiet isolcpus=2,7

Some basics here
access.redhat.com/solutions/480473
Bit more detailed
rigtorp.se/low-latency-guide/

Your config isolates core 2 & 7.

I read a while back about isolating cores that were on the same die....has something to do with cahe and the like. I really wish I could recall that article.

Ok sorted that out. Now how do I know that linuxcnc is running on the last two cpu's, or, how do I force it to run there?

forum.linuxcnc.org/38-general-linuxcnc-q...-irq-affinity#292969

Far more advice than I could give.