Re: [Qemu-devel] Re: Spice project is now open

[Anthony Liguori]

Andrea Arcangeli wrote:
> About the discussion of improving VNC, this code has to change and
> move so fast (you can see already requests from Alexander to split the
> features to allow remote usb from remote qlx, it's expectable code to
> change for the better to support more obscure features than 99% of
> userbase cares about as it goes open), it's huge, it's unreasonable to
> pretend to make official modifications to VNC protocol every time we
> do a small change to the protocol to please Alexander or anybody other
> reasonable wishes of the day, even vnc could eventually reach
> equivalent speedup (which is debatable too). Going the vnc route and
> official feature requests to extend the protocol is a dead hand IMHO,
> all you can argue is spice or something else separate from vnc.
>   

What I really want is a high quality paper comparing Spice to other 
options (like VNC) with performance graphs demonstrating why it's so 
much better.  A paper isn't really necessary but what I'd like to see is 
that level of detailed comparison.

Spice has been closed source for a long time.  For those that have been 
involved with Spice development, I'm sure you understand very well why 
it's so wonderful, but for the rest of us, Spice didn't exist until 
yesterday so it's going to take a little bit for us to all understand 
what actually about it makes it special.

And with respect to the spice protocol, what's the model around making 
changes to the specification?  Is it just submit a patch to the spice 
project?  You complain about VNC's extensibility, but so far, we have no 
idea whether it's even possible to extend Spice.  Given the interactions 
so far, I'm a little concerned about how well we can influence the protocol.

If spice really needs to be able to evolve on it's own, what would it 
take for spice to be implementable from an external process?  What level 
of interaction does it need with qemu?  As long as we can prevent any 
device state from escaping from qemu, I'd be very interested in a model 
where spice lived entirely in a separate address space.

Regards,

Anthony Liguori