Re: [Qemu-devel] [PATCH 0 of 3] vnc and vga improvements

[Anthony Liguori <anthony@codemonkey.ws>]

Stefano Stabellini wrote:
> Hi all,
> This is a three patch series coming from xen-unstable to improve vnc
> and vga performances.
>
> The first patch implements dynamic colour depth changes in vnc.c:
> this way the vnc server can change its own internal colour depth at run
> time to follow any guest resolution change.
>
> The second patch implements the WMVi vnc extension in the qemu vnc
> server, so that we can also notify a vnc client when we change
> internal colour depth and offload any possible colour conversion to the
> client.
>
> The third patch implements sharing of the display pixel buffer between
> vnc.c and vga.c, in order to save a lot of memcpy's.
>
> The idea is that vnc.c (and in the near future sdl.c too) strictly
> follows the guest display resolution and notifies the client of any
> change. As a consequence we can save two colour conversions: one between
> vga and vnc, another one between the vnc server and the vnc client.
>   

I have mixed feelings about this.  On the one hand, reducing the copying 
is a good thing.  On the other hand, we pretty much make it impossible 
to ever support multiple clients.

I'm going to be travelling tomorrow but I'll look through these patches 
in more detail over the weekend.

Regards,

Anthony Liguori

> For the moment this is all, but I'll start working on the sdl shared
> buffer in the next days.
>
> Cheers,
>
> Stefano Stabellini
>
>
>