Re: [Qemu-devel] [PATCH 1/2] qapi: support device id for x-block-latency-histogram-set

[Eric Blake]

On 10/2/18 9:30 AM, Vladimir Sementsov-Ogievskiy wrote:

> > > -# @device: device name to set latency histogram for.
> > > +# @device: device name to set latency histogram for (better use @id).
> > > +#
> > > +# @id: The name or QOM path of the guest device.
> >
> > As long as we are renaming the command, there's no need to keep a 
> > legacy parameter around. Just get rid of device and replace it by id, 
> > rather than worrying about both.  The introduction of the stable 
> > command does not have to carry any baggage left over from the x- 
> > preliminary version.
>
> Libvirt don't need both for now, for different scenarios?

If you want both to work because libvirt has reasons to use both, then 
the documentation needs to be more precise. "(better use @id)" does not 
tell me why I shouldn't use @device, or what difference in behavior I 
get by using one instead of the other. Furthermore, if @id is able to 
use the name of the guest device as an alternative to the QOM path, then 
how is that different from @device being the name of the guest device?

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org