https://bugs.documentfoundation.org/show_bug.cgi?id=158732

--- Comment #2 from Jérôme <[email protected]> ---
On xz decompression speed, the man page of unxz tells :
"On  the same hardware, the decompression speed is approximately a constant
number of bytes of compressed data per second. In other words, the better the
compression, the faster the decompression will usually be."

My xz/unxz version :
-------------
$ unxz --version
xz (XZ Utils) 5.2.2
liblzma 5.2.2
$
-------------

If you want to know a part of the overall installation process performance, we
can pipe the xz decompression process to file extraction process (tar in my
test). I performed the below test with the core deb archive which is the
largest. Of course, I ensured only one terminal ran :
-------------
$ mkdir t
$ dpkg-deb --extract
LibreOfficeDev_24.8.0.0.alpha0_Linux_x86-64_deb/DEBS/lodevbasis24.8-core_24.8.0.0.alpha0-1_amd64.deb
t
$ tar cf sys-tree.tar t
$ xz -9 --threads=1 --stdout sys-tree.tar > sys-tree-9.tar.xz
$ xz -1 --threads=1 --stdout sys-tree.tar > sys-tree-1.tar.xz
$ rm -rf t && mkdir t
$ time ( unxz --to-stdout sys-tree-1.tar.xz | tar xf - --directory t )

real    0m5,969s
user    0m5,992s
sys     0m0,528s
$ rm -rf t && mkdir t
$ time ( unxz --to-stdout sys-tree-9.tar.xz | tar xf - --directory t )

real    0m5,930s
user    0m5,360s
sys     0m0,588s
$
$ rm -rf t && mkdir t
$ time ( unxz --to-stdout sys-tree-1.tar.xz | tar xf - --directory t )

real    0m6,093s
user    0m6,004s
sys     0m0,560s
$ rm -rf t && mkdir t
$ time ( unxz --to-stdout sys-tree-9.tar.xz | tar xf - --directory t )

real    0m5,905s
user    0m5,368s
sys     0m0,624s
$ 
-------------

On my hardware, the core deb archive that has been compressed with the '-9'
force parameter decompresses slightly faster than the archive that has been
compressed with the '-1' force parameter.

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