Well about an hour and a half into it, iglulik puked out an NFS related kernel oops, four of the eight knsfd’s locked up and the machine ground to a halt.  I had to go to the co-lo to reboot and bring it back to a 5.4 kernel along with the other NFS servers.  As a client 5.8 seems to work fine so I left it on those machines which aren’t NFS servers so we still are getting a substantial performance boost.

     I will file yet another bug report with bugzilla but the kernel oops gives it a better chance of getting fixed since it tells them exactly where it was and what it was doing when it barfed, and what it barfed on is a spinlock problem, a spinlock is a kind of lock used to protect critical kernel code that is not thread-safe.