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Re: Adding lzma to dpkg's Pre-Depends

Lucas Nussbaum wrote:
> On 02/04/08 at 01:52 -0700, Steve Langasek wrote:
>> On Wed, Apr 02, 2008 at 10:24:43AM +0200, Lucas Nussbaum wrote:
>>>> So of course besides OOo on there we also find the kernel packages.  We
>>>> wouldn't have to use lzma for the kernels though, if that would raise the
>>>> minimum memory requirements for servers, or lzma could be selectively
>>>> enabled on a per-flavor or per-arch basis as appropriate.
>>> The results are a bit misleading, because they compare the absolute
>>> gain.
>> No, why would that be misleading?  You don't want the overhead of lzma
>> compression for a 10-fold reduction in the size of a package that's already
>> in the bottom 5% of packages by absolute size.
> The overhead (time and memory to compress/uncompress) is likely to be a
> function of the data size. I'm just saying that it's not that simple.
> For example, in the case of OOo, you save 27% of the size, but multiply
> by 4 the time to compress.
> If instead, you use lzma for ttf-arabeyes, smbclient,
> gnome-system-monitor, tomboy, gdb, and language-pack-gnome-en-base, you
> save the same size (10.5M in that case, 10.2M in openoffice's case), but
> you only compress/decompress 43M of uncompressed data in this case,
> while you touch 112M in the OO case. So it's likely that the overhead is
> more important in the OO case.
> I'm just saying that, if we don't use lzma for all packages, it's not
> straightforward to decide for which packages to use it. It's probably a
> function of absolute saving, saving ratio, popcon, etc.
I suggest to use lzma by default on the amd64 architecture, because AFAIK
there are no slow amd64 machines. That means that there is no disadvantage.

The i386 architecture may be used by smaller machines, with less power.
Therefore, we can use lzma there if the application uses much memory,
because we can expect that the memory needed to unpack the package is

The ia64 platform could maybe also use lzma by default, but I have only
limited knowledge about it.

I strongly recommend not to use lzma on embedded architectures.
Julian Andres Klode, Fellow of the Free Software Foundation Europe
                     Debian Maintainer | Developer | Ubuntu Member

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