Re: [Qemu-devel] Re: [PATCH] update server bits on vnc_update

[Gerd Hoffmann]

On 07/21/09 14:56, Stefano Stabellini wrote:
> we call vga_hw_update in vnc_update_client, that means we call it once
> per vnc client connected! We should call it only once, probably in a
> separate timer, that is enabled only if at least one client is connect.

Good point.  Even better would be a timer shared by all clients, then 
loop over all clients (pretty much like vnc_dpy_update calls vnc_update 
for all connected clients).  That would make moving vga_hw_update out of 
the loop trivial ;)

> I also don't like the fact that we are allocating a server surface per
> client connected, this can become a problem very fast: I think we could
> probably get away with just one server surface for all the clients.

I don't think so.  server surface matches the vnc clients view of the 
framebuffer.  We need that to avoid sending screen updates for regions 
which didn't change.  Different clients can have a different views here 
for a number of reasons:  Because they support different feature sets. 
Because we try to skip frames if the pipe is full.  Thus sharing the 
server surface is non-trivial and we'll lose certain optimization when 
doing that.

cheers,
  Gerd