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Re: [libvirt] some unsorted questions



On Thu, Jul 17, 2008 at 10:22:05AM -0400, Cole Robinson wrote:
> Daniel P. Berrange wrote:
> > On Thu, Jul 17, 2008 at 01:29:45AM +0200, Stefan de Konink wrote:
> >> If this gets implemented I would suggest a call that fetches all domains 
> >> from a running system and not only the defined or only the active ones.
> > 
> > This is a good idea regardless. The current APIs require an application
> > todo
> > 
> >    num = list number of domains
> >    for 1 to num
> >        lookup domain by id
> > 
> > In the case of the Xen drivers, this requires  O(n) calls to XenD which
> > are rather expensive. XenD does actually have ability to return data about
> > all domains in a single request. So if we had an API for fetching all
> > domains at once it'd only require  O(1)  expensive XenD calls. I'd imagine
> > something like this
> > 
> > 
> >     int virConnectListAllDomains(virConnectPtr conn,
> >                                  virDomainPtr **domains,
> >                                  int stateflags);
> 
> I've thought about something similar as well. It would also be useful to
> have a command like ListUUIDs with similar state flags, giving apps a
> more light weight manner of polling for domain state changes (ex.
> virt-manager)

A plain ListUUIDs wouldn't be any more efficient - we'd still have to
hit either Xenstore or XenD to get the listing, and once you're doing
that you may as well return the name & ID too in a virDomainPtr object

Daniel
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