feature freeze exception for protobuf support

[Michael Vogt]

Binary package hint: compiz

The latest git version of libcompiconfig (to be released as 0.8.0 soon according to upstream)
 has optional support for the libprotobuf library. This allows caching
of the xml metadata for faster startup. It also means a new dependency against libprotobuf3. There is
a pre-approved MIR for this already (https://wiki.ubuntu.com/MainInclusionReportProtobuf).

It requires also a updates to python-compizconfig (universe).

The settings for compiz and compiz-fusion-plugins-main needs to be adjusted because the old
way of having one global.xml configuration in libcompizconfig is no longer supported with the updated
version. All changes are prepared and tested in the compiz PPA.

Thanks,
 Michael

[Steve Langasek (vorlon)]

My biggest concern here is that the protobuf .deb is around 500K in size, so this costs us another half meg of space on all the CDs. Why is this library so large?

Is this really all for a 476-line XML config file (/usr/share/compizconfig/global.xml)?

[Steve Langasek (vorlon)]

ignore the last question, I see all the xml files under /usr/share/compiz now.

[Martin Pitt (pitti)]

How well has this system be tested? How much does it buy us wrt. startup time?

[Michael Vogt (mvo)]

Its a complex C++ library, this is why its so big. It speeds up the parsing of all the XML data in /usr/share/compiz by building a protobuf based cache of them. This gives me a improvement from 3s to 2.1s startup time for compiz on my system. I don't have a mini9 so I was not able to test it on the reference system.

Its tested by the users of the compiz PPA, me and Seb. Its also default in the upcomming 0.8 release of compiz.

[Steve Langasek (vorlon)]

verbally approved on IRC; the compiz that uses protobuf has been uploaded now, so closing.