Re: [Chicken-users] String compression?

[john]

I noticed this performance hit also with z3. I tried to move the
z3:encode-init procedure outside the loop but it failed. I am
interested in doing some performance comparisons of JSON, XML etc when
compressed so would also like to try out some alternative methods.

John.

On 21/12/06, Graham Fawcett <address@hidden> wrote:
> Hi folks,
>
> Does anyone have code for compressing strings using zlib, lzo or some
> other common llibrary/algorithm? I seem to have z3 working, but the
> performance is really terrible -- I may be doing something wrong, to
> be fair, the documentation is a bit light.
>
> I'm getting ~20x better performance using (process "gzip") to fork
> gzip and compress that way, compared with a string-compression
> procedure that I copied from the z3 test-script:
>
> address@hidden:/tmp$ csi -s compress-test.scm
>
> Test expression is: (string-length (gzip-string *input*))
> Evaluating once. Return value is: 29
> Repeating 1000 times:
>     0.71 seconds elapsed
>     0.02 seconds in (major) GC
>    43478 mutations
>       10 minor GCs
>       16 major GCs
>
> Test expression is: (string-length (z3:compress-string *input*))
> Evaluating once. Return value is: 19
> Repeating 1000 times:
>    17.48 seconds elapsed
>     5.11 seconds in (major) GC
>    16888 mutations
>        3 minor GCs
>     1667 major GCs
>
> I know it's not an apples-to-apples comparison. But why the huge
> difference? My lack of understanding of the z3 egg may be the cause.
>
> Insights (or code!) are welcome. If you have code, I'm really just
> looking for anything that will compress fairly-regular strings
> (s-expresions) of length 2K-20K, with speed favoured over compression.
> I'm considering wrapping LZO but time is a bit short.
>
> Thanks very much,
> Graham
>
>
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