Package: xz-utils
Version: 5.6.0-0.2
Severity: wishlist
After upgrading xz-utils from 5.4.5-0.3 to 5.6.0-0.2, the compression
ratio with "xz -9" has decreased. For instance, on 3 files:
Old 118822308 146463040 157197172
New 121120576 148930624 161255000
It took me some time to figure out. This is the reason:
/usr/share/doc/xz-utils/NEWS.gz
5.6.0 (2024-02-24)
[...]
* xz:
- Multithreaded mode is now the default. This improves
compression speed and creates .xz files that can be
decompressed in multithreaded mode. The downsides are
increased memory usage and slightly worse compression ratio.
[...]
Using -T1 restores the old behavior.
Since this affects what the user gets and is some kind of regression,
this should be announced in NEWS.Debian, IMHO.
Note also that this change might affect diffs between .xz files (e.g.
after something is appended to the uncompressed file), though I have
not checked.
-- System Information:
Debian Release: trixie/sid
APT prefers unstable-debug
APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500,
'stable-security'), (500, 'stable-debug'), (500, 'proposed-updates-debug'),
(500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 6.6.15-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages xz-utils depends on:
ii libc6 2.37-15.1
ii liblzma5 5.6.0-0.2
xz-utils recommends no packages.
xz-utils suggests no packages.
-- no debconf information
--
Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
