Re: [Xen-devel] [RFC] Xen Virtual Framebuffer

[Jon Smirl <jonsmirl@xxxxxxxxx>]

On 06 Dec 2005 00:53:14 +0000, M.A. Williamson <maw48@xxxxxxxxx> wrote:
> And as another also: a big usability benefit of having the framebuffer is
> that users don't have to have a working network or install any extra
> software. It's just a transparency thing; you don't really *need* it but it
> makes domUs behave more like "proper" machines.

You don't need a network outside of the box; you just treat all of the
domains as being wired together with a virtual network inside of the
box.  X already uses Unix domain sockets to talk between apps and the
X server. I would expect a virtualized network running inside the box
to have about the same performance as Unix domain sockets. The X
server already support this socket model today, no new code needs to
be written, Xen just needs to provide the internal virtual network.

> It should also give better performance, as James mentioned. Eventually,
> it'd be nice to support accelerated OpenGL in domUs but that may be some
> way off.

Virtual framebuffer is not going to give you better performance than
the X socket system. I wrote this paper a while ago, it should give
you a good feel of the complexities involved.
http://dri.freedesktop.org/~jonsmirl/graphics.html

>
> Cheers,
> Mark
>
> On Dec 6 2005, James Harper wrote:
>
> >Some things just work better when you can enable shared memory
> >extensions under X, which obviously can't be done over the network.
> >
> >Also, X isn't the only thing that can make use of a framebuffer.
> >
> >James
> >
> >> -----Original Message-----
> >> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> >> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jon Smirl
> >> Sent: Tuesday, 6 December 2005 11:36
> >> To: Anthony Liguori
> >> Cc: xen-devel
> >> Subject: Re: [Xen-devel] [RFC] Xen Virtual Framebuffer
> >>
> >> I haven't tried playing with X and Xen, but why doesn't it work to
> >> just treat the multiple domains like a network? You run X in dom0 and
> >> give it full access to the video hardware. Then you ssh into each
> >> domain and start X apps, just like you do when using X remotely.
> >> OpenGL will even work this way and be accelerated (as soon as X fixes
> >> indirect acceleration). This model should let you get apps up from
> >> each domain simultaneously on the X display in dom0.
> >>
> >> --
> >> Jon Smirl
> >> jonsmirl@xxxxxxxxx
> >>
> >> _______________________________________________
> >> Xen-devel mailing list
> >> Xen-devel@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-devel
> >
> >
> >_______________________________________________
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> >http://lists.xensource.com/xen-devel
> >
>


--
Jon Smirl
jonsmirl@xxxxxxxxx

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