Changing dpkg-deb default compression from gzip to lzma for Hardy

[Thilo Six]

Thilo Six wrote the following on 17.12.2007 15:54

> atached is a more detailed analysis trying to compare gz, bz2 and 7z (aka LZMA).
> I tried it once for (mostly) textfiles as source and once on a binary file in
> both compressing and extraction.

I did the comparion on binaries again.
this time i extracted the .deb first (dpkg -x) cause this is what buildds do,
too.

$ dpkg -x openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb oo/

$ du --max-depth=1 -k | grep oo
112724  ./oo




------------  compression  ----------------

time:					size ($ ls -lk):

bz2
$ time tarbz2 oo.tar.bz2 oo/		37188
real    0m46.918s
user    0m45.503s
sys     0m0.348s


gz
$ time targz oo.tar.gz oo/ 		39084
real    0m14.278s
user    0m13.337s
sys     0m0.264s


7z
$ time tar cf - oo/ | 7za a -si -m0=lzma oo-lzma.tar.7z
real    2m23.783s
user    2m21.409s			27358
sys     0m0.532s


as you can see my first impression was right, 7z is slower but better in
compression (pls remember compression once, extraction many!) then bz2.




------------  extraction  ----------------

time:					size ($ ls -lk):

bz2
$ time untarbz2 oo.tar.bz2		112724 - matches orig
real    0m14.170s
user    0m12.901s
sys     0m0.592s


gz
$ time untargz oo.tar.gz		112724 - matches orig
real    0m3.174s
user    0m1.916s
sys     0m0.332s


7z
$ time 7za x -so oo-lzma.tar.7z | tar xf -
real    0m8.607s
user    0m5.628s			112724 - matches orig
sys     0m0.420s



summary:

at least 7z is faster in extraction than bz2, whereas the compressed 7z is
only ~73,5% of the bz2

gz is the fastest, but produces the biggest compressed files.

-- 
Thilo

key: 0x4A411E09