[Libvir] Re: Asynchronous notifications of domain start/stop

[Daniel P. Berrange]

On Wed, Jul 18, 2007 at 04:13:38PM +0100, Richard W.M. Jones wrote:
> Daniel P. Berrange wrote:
> >The daemon has a buffer of outgoing data - and it appends to this buffer
> >discrete 'XDR' messages. So we should be able to simply append another
> >XDR message per notification & not have to overly worry about things
> >being mixed up in the stream. When the client is deserializing replies
> >during normal calls it'll have to keep an eye out for messages which are
> >in fact notifications, rather than its expected reply, but again that 
> >should not be too hard since we're dealing with discrete XDR encoded
> >messages. So AFAICT we don't need any OOB or piggybacking stuff - just 
> >queue up the data to send as normal.
> 
> Obviously at the moment, remote calls are completely synchronous on the 
> client side.  remote_internal.c:call() is a function which serialises 
> the args, writes them to the socket, then sits there waiting for a 
> reply.  I guess we're not planning to make this asynchronous?  (Or are we??)

It'll be a little tricky, but I don't think we'd want to make it 
asynchronous. If we just adapt it so that if the packet is gets back 
is a notification we put it aside & read another packet for its real
reply. Once its got the real reply then it can dispatch any notifications
it queued up.

Dan.
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