Libvirt slow after a couple of months uptime

[André Malm]

Hello,

I have some issues with libvirtd getting slow over time.

After a fresh reboot (or systemctl restart libvirtd) virsh list / 
virt-install is fast, as expected, but after a couple of months uptime 
they both take a significantly longer time.

Virsh list takes around 3 seconds (from 0.04s on a fresh reboot) and 
virt-install takes over a minute (from around a second).

Running strace on virsh list it seems to get stuck in a loop on this: 
poll([{fd=5<socket:[173169773]>, events=POLLOUT}, 
{fd=6<anon_inode:[eventfd]>, events=POLLIN}], 2, -1) = 2 ([{fd=5, 
revents=POLLOUT}, {fd=6, revents=POLLIN}])

While restarting libvirtd fixes it a restart takes around 1 minute where 
ebtables rules etc are recreated and it does interrupt the service. What 
could cause this? How would I troubleshoot this?

I'm running Ubuntu 22.04 / libvirt 8.0.0 with 70 active VM’s on a 16/32 
core machine with 256GB of ram, CPU is below 50% usage at all times, 
memory below 50% usage and swap 0% usage.

Thanks,
André