[Python-Dev] py2.7: dictobject not properly resizing

[Micha Gorelick]

So I did a bit of benchmarking and attached is the code I used.  With
downsizing happening when ma_used * 2 <= ma_filled, or the following
for the condition in question:

    if (mp->ma_used <= n_used || (mp->ma_fill*3 < (mp->ma_mask+1)*2 &&
mp->ma_used*2 > mp->ma_fill))

I see marginally faster performance with downsizing.  I chose a factor
of 2x because it will ensure downsizings before the ma_fill load
factor comes into play and will also not cause a resize on the next
insert.  Using the vanilla python2.7.3 code, there are never any
resize events where the new size is smaller than the old size.

Cheers,
Micha
-----------------------------
http://micha.gd/
http://github.com/mynameisfiber/
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