When running kvmtop as a service newly added VMs are not added to the output

[mvdboogaard]

We are running kvmtop as a service on our hypervisor. We gather the metrics and send them to prometheus. We noticed that when a new VM is added to the hypervisor this VM is not added to the metrics. It looks like kvmtop is not updating the list of VMs reguallary.
We run kvmtop as follow:
/usr/bin/kvmtop --disk --io --net --host --cpu --mem --verbose -p json -o file --target=////kvmtop.json --targettruncate -f 10

The --targettruncate is added in the code and a PR is open for that one.

The OS of the hypervisor is CentOS Linux release 7.9.2009 (Core)
The QEMU version is from the ovirt repo: qemu-kvm 2.12.0-44.1
The libvirt version is version 4.5.0-36