Re: [PATCH] maint: use an optimal-for-findutils xz compression setting

[Bernhard Voelker]

On 10/28/2017 08:06 PM, Andreas Metzler wrote:
> On 2017-10-28 Bernhard Voelker <address@hidden> wrote:
>> * cfg.mk: Set XZ_OPT = -7e (determined empirically).
>> The compressed tarball size is identical to the default settings (-9e),
>> but using -9e would force every decompression process to use 48 MiB
>> more memory.
> [...]
> 
> I do not think this is a good tradeoff between increasing code size
> (cfg.mk) vs possible performance improvement.

Thanks for your comments.
well, it's just one line of code; the rest are comments, so therefore
I wouldn't bother.

> - Do you expect somebody
> is going to use a system for building find release tarballs that is
> totally memory starved and wil be saved by an additional 48 MiB?

GNU findutils are basic enough that they are likely to be built on
very limited systems/platforms as well.  And if someone actually runs
into that problem, then he would be very grateful for this.

> OTOH -7e is almost two times *slower* than the default. 5.74 seconds vs
> 3.77 on i5-6500.

This is the time for creating the compressed tarball, right?  This is done
only once on a maintainer's system.  I didn't see any noticeable difference
during extraction (on my i5-4570) though.

Coreutils uses -8e for the same reason [1], so I think it's worth here as
well.  I'll adjust to -8e then, WDYT?

[1] https://git.sv.gnu.org/cgit/coreutils.git/tree/cfg.mk?id=61a8b5cb56#n37

Have a nice day,
Berny