Re: [Xen-devel] Re: Re: Install paravirtualized drivers after bootingforhigh-performance IO

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

>     As i recognized, paravirtulization is an implemention of high
> performence virtulization in non-VT box, pure virtulization needs no
> modification on guest os, but paravirtulization do needs. Is that right?

Yes, that's all correct.

>     If so, guest os on VT cpu will provide no paravirtulization?

A fully virtualised environment will be available for guests on a VT CPU, so 
they won't *need* any modifications in order to run.  However, for good IO 
performance, you're likely to want to install Xen-aware device drivers which 
will be compatible with the existing frontend/backend scheme.

Other fully virtualised environments (e.g. VMWare) also sometimes provide 
higher-performance drivers that are aware of the environment.  In Xen's case 
we have Xen-aware drivers already but they need to be adapted to run in a VT 
virtual machine

HTH,
Mark

>     Any suggestions?
>
> Miao
> StarSoftComm.com
>
> Arlen.D.Wang wrote:
> >What is the difference between paravirtualized and virtualized?
> >
> >
> >DengYu  Wang
> >
> >>Where is get  a reference to the Windows support using Vanderpool
> >>Technology ?
> >
> >The code in the unstable tree is the best reference (if you feel brave).
> >There are the slides for a couple of talks about VT at the Xen Summit
> >webpage
> >(http://summit.xensource.com/presentations/).
> >
> >>Who is doing that Windows support using Vanderpool Technology ?
> >
> >This implementation work has been spearheaded by Intel, although I think
> >there
> >are also some people at IBM also working on Xen/VT (is that right?)
> >
> >>If Xen can run unmodified Linux , then Xen can run unmodified Windows
> >> also , right ?
> >
> >Not yet: running Windows requires emulating extra 16 bit x86 stuff that
> >Linux
> >doesn't need in order to run.  There is a design for supporting this and
> > it might even be under development right now.
> >
> >HTH,
> >Mark
> >
> >>DengYu  Wang
> >>
> >>"Mark Williamson" <mark.williamson@xxxxxxxxxxxx>
> >>§Õ?:200505091257.04034.mark.williamson@xxxxxxxxxxxxxxx
> >>
> >>>Hi there,
> >>>
> >>>I expect you've seen a reference to the Windows support using Vanderpool
> >>>Technology?
> >>>
> >>>The current VT implementation provides an emulation of real hardware
> >>>devices
> >>>(e.g. an NE2000 ethernet card) to the guest OS.  This has the advantage
> >>>that
> >>>you can boot an unmodified OS and it'll recognise the emulated devices
> >>>and Just Work.  This will allow you to install the OS using its usual
> >>>installer
> >>>and get things up and running.
> >>>
> >>>However, you pay a performance price for emulating a device like this.
> >>>The
> >>>most straightforward way to solve this is to replace the emulated device
> >>>drivers with Xen-aware drivers (like the ones used by the Xen-native
> >>>Linux port).  Once you've installed the OS, you can upgrade to the Xen
> >>>device drivers.
> >>>
> >>>This should give better bandwidth for things like disk and network IO.
> >>>
> >>>Does that help?
> >>>
> >>>Cheers,
> >>>Mark
> >>>
> >>>>    What is "high-performance IO" ?
> >>>>    What meaning for "Install paravirtualized drivers after booting for
> >>>>high-performance IO"?
> >>>>
> >>>>    Thanks,
> >>
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