Let's step back a bit

Posted Jun 3, 2009 22:21 UTC (Wed) by nix (subscriber, #2304)
In reply to: Let's step back a bit by Thue
Parent article: Xen again

But KVM is just a speedup component for qemu, really. If you don't have
KVM, qemu still works, only slower (much slower if you don't load kqemu).

If you don't have VT support, my understanding is that Xen similarly
works, just slower.

So what's the substantive difference?

Let's step back a bit

Posted Jun 3, 2009 23:01 UTC (Wed) by nevets (subscriber, #11875) [Link] (1 responses)

I believe that a paravirtualized guest runs much faster than a qemu guest. But I have not taken any benchmarks.

I also think the issue is that Xen is still quite a head of KVM in features, but this too is slowing down.

Let's step back a bit

Posted Jun 4, 2009 2:34 UTC (Thu) by drag (guest, #31333) [Link]

> I believe that a paravirtualized guest runs much faster than a qemu guest. But I have not taken any benchmarks.

YES PV is massively faster then just plain Qemu. Massively faster in all respects. The overhead of Xen PV vs naked hardware is going to be just a few percent.

Of course this requires modification to the guest.