[Etoys] zip optimization results

Ties Stuij cjstuij at gmail.com
Thu Apr 10 09:05:19 EDT 2008


I got some interesting results from fiddling with various project
zipping strategies on the XO.

Basically using only the unzipped project file, big projects load
about 3 times faster than the doubly zipped alternative (where the
project zip bundle is not compressed); which is the way project files
are stored now.

Numbers are in seconds, horizontally we see the zipping methods and
vertically three different projects. On a clean 3.0 image, loaded with
our customizations and luke's speed patch.

         1         2              3           4              5
tr      37       1.20       1.29       1.29       46
c10  30      1.15       1.23        1.23       40
shp  18         30           32          36        20

tr = triangle identification
c10 = adding to 10 is fun
shp = counting sheep

1 = non-zipped stand-alone .pr file
2 = zipped .pr file in uncompressed archive
3 = non-zipped .pr file in uncompressed archive
4 = non-zipped .pr file in compressed archive
5 = zipped stand-alone .pr file

Testing the other 1.20m plus activities also shows a threefold speedup
to generally just under 40 sec against the 2.3 image with luke's
dictionary patch loaded.

For us at OLE the obvious choice is 1, cause we basically just go for
raw speed, but I guess there's something to say for 5, because it does
cut the size of the files in half. To me it seems worth it on the XO,
but others might not be as performance inclined. Or?

In general, fascinatingly enough, doubly zipped projects seem to load
faster than bundles with a zipped .pr file in them.

Attached the patches that made this work:

The patches I already sent. Useful irrelevant of the patches that
follow them in this post:
fileIn Fix: for unzipped .pr files the wrong kind of stream is created
(i think).

AsUnzippedStream: don't use unzip routine with built in progress bar.
Speedup of about 20% on the larger files. Note that this doesn't have
anything to do with the project progress bar.

new ones (names are a bit misleading). Basically just throw in the
ones whose effect you want. For a combination of bundle and
uncompressed .pr file, make sure you've got the fileIn Fix loaded:
zipOptimizations: don't zip the inner .pr file

furtherZipOptimizations: don't zip the bundle and don't create the
other files in the bundle (html file, etc...).

compress project bundle: If filed in, the project bundle is compressed.

Hope any of this is of use to some.


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