DBus/QtDBus Concerns

[Waldo Bastian]

On Tuesday 11 July 2006 22:33, Gary Cramblitt wrote:
> 1.  Performance.  At least one benchmark puts DBus at 6 times slower that
> DCOP.  Now benchmarks are frequently misleading, but this does raise a risk
> flag.  Wouldn't it be a tragedy if KDE4 were released and the community's
> reaction were "Wow, looks great, but runs too darn slow."  Has anyone
> actually run some performance testing approximating the KDE environment?
>
> http://eleceng.dit.ie/frank/rpc/CORBAGnomeDBUSPerformanceAnalysis.pdf

The key is to make sure you don't do unnecassery round-trips and don't send 
enormous amounts of data. Once you do that actual performance shouldn't be a 
big factor. Your concerns wrt QtDBus suggests there may be some issues wrt 
round trips that should be solved.

> 2.  IDL Documentation.  The DBUS IDL specification does not permit
> programmer's to document their interfaces in the xml files.   This is a
> recognized problem with at least two aspects: 1) The need to provide
> interface documentation at run time (introspection), and 2) The need to
> provide more extensive documentation for programmers.  Presently, we have
> to provide documentation separately from the IDL xml file, which is a
> formula for errors.

Introspection has been a topic of discussion on the DBUS mailinglist in the 
last week or so. It's something that everyone would like to solve but there 
was some uncertainty about the exact format and how much info to include.

> 4.  Maturity.  This statement in the DBus 0.62 README says it all.
>
> "Until 1.0 is released, feedback that requires API changes may be
> incorporated into D-BUS. This may break the API, the ABI, the
> protocol, or all three.
>
> Until 1.0 is released, you have to define -DDBUS_API_SUBJECT_TO_CHANGE
> just as a safety check to be sure everyone is aware of this API/ABI
> policy and has the right expectations."

DBUS developers are currently working on DBUS 0.90 in preparation of a 1.0 
release. Although it's nice to have 1.0 it also means that it becomes a lot 
harder to fix things. Having KDE run with DBUS before it hits 1.0 allows a 
reality check to see if DBUS as it is is usable as a DCOP replacement.

Cheers,
Waldo
-- 
Linux Client Architect - Channel Platform Solutions Group - Intel Corporation
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 191 bytes
Desc: not available
URL: <http://mail.kde.org/pipermail/kde-core-devel/attachments/20060712/4c9ee98f/attachment.sig>