[libvirt] [dbus PATCH 18/25] Implement PinEmulator method for Domain Interface

[Daniel P. Berrangé]

On Wed, Apr 18, 2018 at 03:44:51PM +0200, Pavel Hrdina wrote:
> On Wed, Apr 18, 2018 at 02:41:19PM +0100, Daniel P. Berrangé wrote:
> > On Wed, Apr 18, 2018 at 03:03:20PM +0200, Pavel Hrdina wrote:
> > > On Tue, Apr 17, 2018 at 02:04:37PM +0200, Katerina Koukiou wrote:
> > > > Signed-off-by: Katerina Koukiou <kkoukiou at redhat.com>
> > > > ---
> > > >  data/org.libvirt.Domain.xml |  6 ++++++
> > > >  src/domain.c                | 34 ++++++++++++++++++++++++++++++++++
> > > >  2 files changed, 40 insertions(+)
> > > > 
> > > > diff --git a/data/org.libvirt.Domain.xml b/data/org.libvirt.Domain.xml
> > > > index f2ef3dd..97c5471 100644
> > > > --- a/data/org.libvirt.Domain.xml
> > > > +++ b/data/org.libvirt.Domain.xml
> > > > @@ -268,6 +268,12 @@
> > > >          value="See https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainMigrateStartPostCopy"/>
> > > >        <arg name="flags" type="u" direction="in"/>
> > > >      </method>
> > > > +    <method name="PinEmulator">
> > > > +      <annotation name="org.gtk.GDBus.DocString"
> > > > +        value="See https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainPinEmulator"/>
> > > > +      <arg name="cpumap" type="ay" direction="in"/>
> > > 
> > > We need to figure out a better way how to represent the CPU map in
> > > libvirt-dbus.  IMHO using an array of unsigned char is not the best
> > > from for D-Bus.
> > > 
> > > There are two possible forms, using the string representation as we
> > > have in virsh, so for example "0,3-7,^5" which is 10011011.
> > > 
> > > The second form is the one that libvirt-python uses, a tuple of boolean
> > > values, which in case of D-Bus would be represented as array of boolean
> > > values.
> > 
> > array of boolean is better than array of char in that it is explicitly
> > typed. It is inefficient though - each boolean value takes up 32-bit on
> > the wire !
> > 
> > > The first form is better suited for humans so I guess we should go with
> > > the second form in D-Bus.
> > 
> > Ultimately you should think about how a dbus client will consume the
> > data. If you use  array of boolean, that all the DBus clients will
> > map that into native boolean types which are easy to acess for apps.
> > 
> > If you use the string syntax, then every application has to write
> > parsing & formatting code for this syntax.
> 
> I completely agree, that's why I suggested using an array of boolean.

Yeah, my gut feeling is that array of boolean is best despite the
wire inefficience.

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|