Re: [Qemu-devel] Doing a Tcl/Tk based frontend

[Daniel P. Berrange]

On Fri, Jun 16, 2006 at 01:33:26AM +0200, Oliver Gerlich wrote:
> Daniel P. Berrange schrieb:
> > On Thu, Jun 15, 2006 at 05:52:14PM -0500, John Morris wrote:
> > With the new VNC server capability there is no need to embed the emulator's
> > existing window. You can just have a GTK/QT widget which acts as a VNC 
> > client
> > taking the video feed & displaying directly within the GUI management app. 
> > Similarly you can redirect the QEMU monitor console to a UNIX pipe when 
> > lauching QEMU, so the management app can fully control the QEMU engine
> > to do suspend/resume, snapshots, media changesi.
> > 
> > I wrote an GUI app in Python which did the latter already:
> > 
> > http://people.redhat.com/berrange/olpc/sdk/olpc-qemu-admin-demo.html
> > 
> > At the time I wrote it there wasn't any VNC support in QEMU, so I couldn't
> > hook up the display, but with the 0.8.1 release it wouldn't be much effort
> > to embed the display directly in the app via VNC. So I don't think there 
> > are any changes required in QEMU itself to be able to create a fully
> > featured QEMU frontend easily on a par with VMWare Desktop, if not better.
> > 
> > Regards.
> > Dan.
> 
> VNC is a good idea... But isn't it a bit "laggy" for this purpose? I
> think people accept a laggy mouse cursor in a VNC window that comes over
> the network, but won't really accept that in virtual machine that's
> running directly on their desktop. OTOH, I'm no VNC expert :) and maybe
> there are tricks to speed this up?!

There is no performance issue with native VNC on either localhost or
a LAN. I know of places where people use a VNC session to a remote
Linux desktop for day-to-day software development with no serious
performance issues. Basically if your network is reasonably fast then
there should be no issues. NB, I'm talking LAN - not WAN / Internet
here, so assuming 100mb ethernet.

That said its possible that a combination of VNC, and slow emulation
of the display adapter within the guest OS could lower performance a
bit more, but I'm still fairly optimistic that its usable. In any
case slow display adapter emulation would affect the native SDL display
mode too.

Dan
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