Bug#832010: Please enable LZ4 compression

[Michael Biebl]

Am 21.07.2016 um 19:28 schrieb Yuri D'Elia:
> On Thu, Jul 21 2016, Michael Biebl <biebl at debian.org> wrote:
>> And in Debian we build against libxz, so xz compression is used for core
>> files.
> 
> Indeed, and it's pretty slow.
> 
>> What would we gain by switching from xz to lz4. Can you provide numbers?
> 
> I don't have enough time to back it up comparing exactly the difference
> between LZ4 and XZ in coredump, but if you compare regular XZ to LZ4 you
> can expect anywhere between 10x and 50x improvement in compression
> speed while maintaining an acceptable compression ratio.

So, building systemd with lz4 support means, that
/lib/systemd/libsystemd-shared-*.so and /lib/*/libsystemd.so.* will get
a dependency on liblz4. liblz4 on the other hand is installed in /usr/lib.

The /lib/systemd/systemd binary itself links against libsystemd-shared
(interestingly, our debian/rules check seems to not have caught this).

So, we can finally give up on the idea of split-usr and no initramfs
(and need to communicate that) or have liblz4 moved from /usr/lib to
/lib first.

liblz4 should probably gain a Build-Depends-Package line in that case,
so we can enforce a tight enough dependency. Like it was done for
libapparmor. Atm, the dependency we get via the symbols file is (>=
0.0~r113)


-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: OpenPGP digital signature
URL: <http://lists.alioth.debian.org/pipermail/pkg-systemd-maintainers/attachments/20161109/3da57da2/attachment.sig>