Message151850
> To see the collision counting, enable the DEBUG_DICT_COLLISIONS
> macro variable.
Running (part of (*)) the test suite with debugging enabled on a 64-bit
machine shows that slot collisions are much more frequent than
hash collisions, which only account for less than 0.01% of all
collisions.
It also shows that slot collisions in the low 1-10 range are
most frequent, with very few instances of a dict lookup
reaching 20 slot collisions (less than 0.0002% of all
collisions).
The great number of cases with 1 or 2 slot collisions surprised
me. It seems that there's potential for improvement of
the perturbation formula left.
Due to the large number of 1 or 2 slot collisions, the patch
is going to cause a minor hit to dict lookup performance.
It may make sense to unroll the slot search loop and only
start counting after the third round of misses.
(*) I stopped the run after several hours run-time, producing
some 148GB log data. |
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Date |
User |
Action |
Args |
2012-01-23 21:39:32 | lemburg | set | recipients:
+ lemburg, gvanrossum, tim.peters, barry, georg.brandl, terry.reedy, gregory.p.smith, jcea, mark.dickinson, pitrou, vstinner, christian.heimes, benjamin.peterson, eric.araujo, grahamd, Arfrever, v+python, alex, zbysz, skrah, dmalcolm, gz, neologix, Arach, Mark.Shannon, eric.snow, Zhiping.Deng, Huzaifa.Sidhpurwala, Jim.Jewett, PaulMcMillan, fx5 |
2012-01-23 21:39:31 | lemburg | link | issue13703 messages |
2012-01-23 21:39:31 | lemburg | create | |
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