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

thanks

Suresh