[Python-Dev] py2.7: dictobject not properly resizing (original) (raw)
Micha Gorelick mynameisfiber at gmail.com
Sun Mar 31 18:51:26 CEST 2013
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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
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