[Vm-dev] Issue 99 in cog: Link LZ4 Compression

David T. Lewis lewis at mail.msen.com
Sat Oct 13 16:34:49 UTC 2012

On Sat, Oct 13, 2012 at 05:07:40PM +0200, Camillo Bruni wrote:
> > 
> > IIUC there's an unspecified (probably non-public/not open source) project. You'd like to do some experiments with it (because you have access to it) and therefore you want to add some extra code (not useful for most users) to the public VM (used by everyone) to support that expriment. Am I right?
> sorry, but you're quite wrong about that.
> a) if anything I produce open source artifacts
> b) I do research
> c) I work on pharo
> I am looking forward to improve our system and having a state of the art
> compression library at hand might be useful. besides that I prefer shipping
> a slightly overloaded VM to the community for the sake of wider functionality.
> For instance we have the SSL plugin by default now, which is kind of something
> you'd expect from any 2012 programming language.
> We plan on adding the sources / ast to the image, a perfect use-case for a nice
> compression library.

If you are looking for a use case to actually test and measure the
performance differences, the source file stream might be a good use
case. Start by moving it into the image so the sources "file" is in
the image rather than stored on disk. Then do the same with a compressed
sources file (an stc file created with "Smalltalk compressSources"). The
uncompressed version will be about 4 times larger than the compressed
one, so you could measure performance impact there. Finally, add your
LZ4 compression and do a version of compressed sources that uses LZ4.
Test it and see if it is measurably better or worse than zip compression.


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