Re: [PATCH v4 6/6] virtio: Add VIRTIO_F_IN_ORDER property definition

On Mon, Jul 22, 2024 at 1:11 PM Eugenio Perez Martin
<[email protected]> wrote:
>
> On Sat, Jul 20, 2024 at 9:16 PM Michael S. Tsirkin <[email protected]> wrote:
> >
> > On Wed, Jul 10, 2024 at 08:55:19AM -0400, Jonah Palmer wrote:
> > > Extend the virtio device property definitions to include the
> > > VIRTIO_F_IN_ORDER feature.
> > >
> > > The default state of this feature is disabled, allowing it to be
> > > explicitly enabled where it's supported.
> > >
> > > Acked-by: Eugenio Pérez <[email protected]>
> > > Signed-off-by: Jonah Palmer <[email protected]>
> >
> >
> > Given release is close, it's likely wise.
> > However, I think we should flip the default in the future
> > release.
> >
>
> Should we post a new version with v9.2 tag enabling it?
>

Sorry, actually I think this needs some more thought. Maybe in_order
hurts the performance of devices that are usually out of order, like
blk. Should we enable only for virtio-net and let each device code
decide?

> > > ---
> > >  include/hw/virtio/virtio.h | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> > > index fdc827f82e..d2a1938757 100644
> > > --- a/include/hw/virtio/virtio.h
> > > +++ b/include/hw/virtio/virtio.h
> > > @@ -373,7 +373,9 @@ typedef struct VirtIORNGConf VirtIORNGConf;
> > >      DEFINE_PROP_BIT64("packed", _state, _field, \
> > >                        VIRTIO_F_RING_PACKED, false), \
> > >      DEFINE_PROP_BIT64("queue_reset", _state, _field, \
> > > -                      VIRTIO_F_RING_RESET, true)
> > > +                      VIRTIO_F_RING_RESET, true), \
> > > +    DEFINE_PROP_BIT64("in_order", _state, _field, \
> > > +                      VIRTIO_F_IN_ORDER, false)
> > >
> > >  hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n);
> > >  bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n);
> > > --
> > > 2.43.5
> >