I have read that in para virtualization hosted virtual machines are aware that they are being virtualized, and this allows them to increase their performance. But, how does the hosted machine know they are virtualized as since we are not modifying any kernel parameters of the guest os while installing?
What do we need to do on the host OS to give it a performance increases resulting from recognising that it is in a virtual environment? What are the best ways to optimize a Ubuntu VM for in an xen environment?