Re: [Qemu-devel] [PATCH] vnc: shared buffer: skip some optimizations.

[Anthony Liguori <anthony@codemonkey.ws>]

Gerd Hoffmann wrote:
>   Hi,
>
> When using a shared display surface buffer some of the optimizations
> done by the vnc server code don't work.  In shared buffer mode the guest
> may update the screen while the vnc server looks at the framebuffer.
> That in turn makes some code racy, the dirty bitmap walk through for
> example, leading to screen corruption.  Right now this is visible with
> xenfb only.  I expect simliar issues will show up for vga too once we
> run the vcpus in threads.
>   

:-/  I'd rather disable the shared buffers.

The minimization optimization is extremely important for VNC 
performance.  It's a much bigger win than the memory copy that you lose 
when using shared buffers.

Regards,

Anthony Liguori

> please apply
>   Gerd
>