/proc file system data for Virtual machine process (KVM originated)

[dubi]

a Virtual Machine (VM) under KVM is a process with threads.
in the host /proc/ file system under this process appear threads by the number of vcpus allocated to the VM
(see /proc/<VM process ID>/task/ ) at VM generation time.
when the VM is idle or CPU bound we see at the host only these vcpu threads .If a combined cpu and i/o load is run on the VM - some other threads appear under the VM process . Those addtional threads appear to be sleeping or in Disk wait state . I cannot track them in running state . If they do use a CPU -do they run on the VM vcpu threads ( which serve them as worker threads) or they use host CPUs allocated to them separately at the expense of the vcpu threads ?

[Rubberman]

Great question! Unfortunately, I am clueless here! I understand that when you tell the VMM that a specific VM will utilize 2 cores, then it will allocate a thread for each, allowing the VM threads to switch as necessary to available cores. Other than that, I haven't delved into the murky guts of the KVM. With luck, I won't ever have to! As they say, if the magic works, who cares? My current work problems are much more mundane, but difficult nonetheless. I think I'll keep my intellect on those problems since that work will affect the success of many 100's or 1000's of people and their careers...