I'm trying to create a clone of a physical Window VM using p2v. 

My goal is to create a cloning tools VM that has libguestfs tools installed and acts as the convertor. 
VM conversion works just fine but the conversion rate is significantly slow(1/3) when running inside the VM compared to when the v2v is run on the same bare-metal host.

On the host:
./virt-p2v-20190405-w1f4efxy/virt-v2v-conversion-log.txt:virtual copying rate: 615.9 M bits/sec
./virt-p2v-20190405-w1f4efxy/virt-v2v-conversion-log.txt:real copying rate: 181.8 M bits/sec

From the Guest VM (On the same bare-metal host)
virt-p2v-20190405-95azj89j/virt-v2v-conversion-log.txt:virtual copying rate: 185.1 M bits/sec
virt-p2v-20190405-95azj89j/virt-v2v-conversion-log.txt:real copying rate: 62.7 M bits/sec

I understand there are several factors come into play but i tried to make the VM comparable by making sure enough CPU / memory is given to the VM. Also the I played by adjusting the disk cache modes for the VM(cache=none, cache=unsafe).  When the conversion happens there is not much load and there are no other VMs on this machine.

I ruled out the disk being the bootleneck because when i do "virt-v2v -i disk" conversion the VM is only slightly off.
For the same disk image,
virt-v2v when running in the host took '75 sec' whereas in the VM it took '100 sec'

How to go about debugging this performance issue? Any pointers would be helpful