Antwort: [Mod_gzip] mod_gzip compression level

[Peter J. Cranstone]

Hi All,
Peter here...

Kevin and I did a lot of testing wit mod_gzip and determined the best
compression level "for the buck" was 6.

Changing it around made some differences but not enough to warrant a
change to a higher level which will slow things down.


Peter



-----Original Message-----
From: mod_gzip-admin@lists.over.net
[mailto:mod_gzip-admin@lists.over.net] On Behalf Of
Michael.Schroepl@telekurs.de
Sent: Wednesday, March 05, 2003 6:00 AM
To: mod_gzip@lists.over.net
Subject: Antwort: [Mod_gzip] mod_gzip compression level


Hi,


> I have compiled  mod_gzip-1.3.26.1a with apache_1.3.27.
> Is it possible to modify the compression level?

We have tried to isolate the place inside the source code
where the compression level has been set.

But after some discussion with Kevin Kiley it looked as if
there is not such place where you can simply switch the
compression level to any value you want. I don't remember
the details, but maybe Kevin didn't implement some parts
of the level 7-9 algorithm, as he decided to use level 6
anyway ... on the other hand, it might rather be possible
to use some lower level (if you want to save CPU load).

> If so can you point me to a place that documents how to do it?

If I knew how to do it, there would be such a document
(and there would even be a configuration directive in
mod_gzip 1.3.26.1a).

But if you are of the adventurous type, then take the source
code and read mod_gzip_compress.c.

line 1197 reads like this:
      gz1->level       = 6;
So this one _might_ be the place to change the compression
level ... but I don't guarantee that mod_gzip will still
work correctly. This is undiscovered territory ...

Regards, Michael


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