FreeBSD on Xen with hw virtualization support

[Bruce Simpson]

On 03/20/10 16:19, Bruce Simpson wrote:
>
> There is a performance penalty, because Xen has to emulate real 
> hardware for HVM, using code largely cribbed from QEMU.
>
> Normally this happens within the hypervisor itself, however, this is 
> problematic, because there is then no good way to book the 
> CPU/memory/IO involved to the domU doing the I/O. This in turn affects 
> scheduling parameters.

Correction: mostly dom0 with some hypervisor bits on top.

But this still screws up HVM domU accounting.

In a hosting environment, this is all important. Chisnall's Xen book 
explains this in great detail.