[Python-Dev] New regex module for 3.2?

[Stefan Behnel]

Gregory P. Smith, 27.07.2010 07:40:
> A max cache size of 100 was too small.  I just increased it to 500 in the
> py3k branch along with implementing a random replacement cache overflow
> policy.  It now randomly drops 20% of the compiled regular expression cache
> instead of simply dropping the entire cache on overflow.
>
> With the regex_v8 benchmark, the better cache replacement policy sped it up
> ~7% while raising the cache size on top of that (likely meaning the cache
> was never overflowing) sped it up ~25%.
>
> Random replacement without dropping everything at least means apps thrashing
> the cache degrade much more gracefully.

The same algorithm should be helpful in ElementTree's ElementPath module.

Stefan