Re: [Qemu-devel] QAPI conversion status and async commands support

[Alon Levy <alevy@redhat.com>]

On Wed, Mar 07, 2012 at 10:06:31PM +0200, Alon Levy wrote:
> On Wed, Mar 07, 2012 at 11:36:06AM -0600, Anthony Liguori wrote:
> > On 03/07/2012 11:29 AM, Paolo Bonzini wrote:
> > >Il 07/03/2012 17:36, Luiz Capitulino ha scritto:
> > >>Hi there,
> > >>
> > >>In the last few weeks we've had some proposals for new QMP commands that need
> > >>to be asynchronous. As we lack a standard asynchronous API today, each command
> > >>ends up adding its own way to execute in the background.
> > >>
> > >>This multiplies the API complexity as each command has to be implemented and
> > >>learned by clients separately, with their own way of doing more or less the
> > >>same things.
> > >>
> > >>The solution for this, envisioned for us for a long time now, is to introduce
> > >>an unified QMP API for asynchronous commands.
> > >>
> > >>But before doing this we have to:
> > >>
> > >>   1. Finish the commands conversion to the QAPI
> > >>
> > >>      This is almost done, the only missing commands are: add_graphics_client,
> > >>      do_closefd, do_device_add, do_device_del, do_getfd, do_migrate,
> > >>      do_netdev_add, do_netdev_del, do_qmp_capabilities and do_screen_dump.
> > >>
> > >>      Note that do_migrate has already been posted to the list, and I have
> > >>      the screendump more or less done. Also, Anthony has an old branch where most
> > >>      of the conversions are already done, they just need to be rebased&  tested.
> > >>
> > >>   2. Integrate the new QAPI server
> > >>
> > >>      Implemented by Anthony, may have missing pieces.
> > >>
> > >>   3. Implement async command support
> > >>
> > >>
> > >>I think the missing commands to be converted can be done in around one week,
> > >>but unfortunately I've been busy at other things and will need a few days to
> > >>resume this work. Then there's the new QAPI server&  async support, which I'm
> > >>not sure how much time we'll need to integrate them, but we should have this
> > >>done for 1.1.
> > >>
> > >>The main question is: what should we do for the already posted async commands?
> > >>Should we hold them until we finish this work?
> > >
> > >I think yes, and we could even have a list of features without which 1.1
> > >should not ship.  QOM buses, drive mirroring and QAPI async command
> > >support may be them.  Perhaps qtest too.
> > 
> > Okay, let's get serious about what we can and can't do.
> > 
> > Hard freeze for 1.1 is May 1st which is roughly 6 weeks from now.
> > 
> > I think QOM buses can go in no problem along with qtest.  I would be
> > okay considering QOM buses a release blocker but probably not qtest.
> > 
> > I'm not really sure about drive mirroring.  Is the work already done
> > such that we just need to talk about merging it?
> > 
> > With QAPI async command, I don't think 1.1 is a viable target.
> > We're not just talking about converting existing commands to QAPI,
> > but also replacing the QMP server infrastructure.  I don't think
> > that is a change that should be made at the tail end of the
> > development cycle.
> 
> ... so, Avi, Anthony, as:
> 1. screendump is broken for qxl
> 2. there will not be QAPI async for 1.1
> 3. monitor async is unacceptable by maintainer
> 
> Is screendump-async to be accepted?

I've send a patchset that works for hmp and I intend to fix libvirt by
using the hmp screendump command instead of the qmp one for now. See:
 http://lists.gnu.org/archive/html/qemu-devel/2012-03/msg01802.html

> 
> > 
> > Regards,
> > 
> > Anthony Liguori
> > 
> > >
> > >Paolo
> > >
> > >
> > >
> > 
> > 
>