> If I understand that paper correctly, HVM+VT-d outperforms PV by quite a
> lot (if you have VT-d support on your system).
>

Thanks for that link. Just to make my criticism of the initial claim more
clear: I don't claim that HVM can never be faster than PV but that you need
to understand when exactly this is the case. For example I'm not sure that
x86_64 vs. x86 really enters into this but I can definitely see VT-d making
an impact there.

Regards,
Dennis

Even though this is Intel talking I'd still be very sceptical of getting those numbers since this is quite the opposite of what I've seen.
Maybe the vt-d is getting good enough to actually accelerate IO operations but even so that would only happen on the latest hardware.

I will say that Xen has a really long packet path though.

Grant McWilliams