Bug#691027: src:iceape: please use xz compression for source and binaries

Andrey Mitrofanov abme at rambler.ru
Sat Oct 20 12:13:55 UTC 2012


Source: iceape
Version: 2.7.9-1
Severity: normal
User: ansgar at debian.org
Usertags: xz-for-wheezy


Hi, pkg-mozilla-maintainers and everyone concerned!

Please use xz complession for iceape package source and
binaries to save mirror space, user download and insattation
times, even some wasted polycarbonate rounds :) in the end.

I made that in several easy ;) steps while doing a rebuild
of iceape 2.7.9-1 for squeeze.

* Unpack the current, 2.7.9-1 in my case, source.

* Repacking .orig.tar-s from bz2 to xz got me impressive 22.5Mb
  off out of 109Mb. Tthats -20.7%!

  + Somth.like this would do:

  $ for f in *.orig*.tar.bz2; do bunzip2 $f; xz -9ev ${f%.bz2}; done

* Add debian/source/options and override_dh_builddeb clause like
  in the patch attached.

  First will make a .debian.tar.xz w/even more imressive -25.4% gain in
  size - from the venerable .gz (not that "big" in :) megabytes thou).

  Second will do the better compression of the binary packages at the
  re-buld time. Got me -54.9Mb or -34.8% (of original 157.8Mb) in my
  28 i386+all .deb-s rebuild (and yeah, 51.9Mb of them -- off one
  iceape-dbg package.)

* Pack the source package back.

* Rebuild it. (I used pbuilder and some local backports mix.)

  + Check the ressuling data.tar in .deb-s is xz compressed:
$ ar tv abm0+xz/iceape-dbg_*.deb 
rw-r--r-- 0/0      4 Oct 17 23:18 2012 debian-binary
rw-r--r-- 0/0   1075 Oct 17 23:18 2012 control.tar.gz
rw-r--r-- 0/0 74228460 Oct 17 23:23 2012 data.tar.xz

I gained total of -77.6Mb / -29%for src+i386+all off orignal 266.8Mb.
Guess other Debian binary archs would add some more to this will the
proposed change make its way to the archive.

As for extra resources used to achieve this... Several minutes maybe
of CPU time for more intensive uncompression of source and compression
of the result is neglectable camparing to overall 1h+ build time, and
is a clear win considering multiple download time gains for the users.
Memory consumption for source xz unpack (64+Mb for the sources packed
with -9e option as above) and .deb compress (94+Mb for the campression
level I got in my build -- dont know :) how to coerce build-deb to use
-9e maximum compression, and resulting data.tar.xz-s seem to be
compressed w/some default needing 8Mb+ for decompression, thus the 94Mb
figure as for man xz) is at least comparable to memory usage of the
actual build. User time used for unpacking of these xz compreaased
.deb-s increases slightly though (like 3.2s -> 9.9s on my test machine
for the [cache-hot] {z,xz}cat data.tar.{z,zx} >/dev/null for that
_largest -dbg package).

New archivers is such a recreative topic dont you agree? :))


And many thanks for the stable Mozilla Suite Dabian package!


...Be happy, take it easy, sayonara.
---abme at rambler dot ru
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