On Thu, Jul 22, 2010 at 3:26 PM, Nick Coghlan <ncogh...@gmail.com> wrote:
> On Fri, Jul 23, 2010 at 12:42 AM, Georg Brandl <g.bra...@gmx.net> wrote: > > Sure -- I don't think this is a showstopper for regex. However if we > don't > > include regex in a future version, we might think about increasing > MAXCACHE > > a bit, and maybe not clear the cache when it reaches its max length, but > > rather remove another element. > > Yikes, I didn't know it did that. That certainly sounds like it should > be an RFE in its own right - some basic form of Least Recently Used > accounting should be beneficial (although the extra bookkeeping might > hurt scripts that aren't hitting the cache limit). > > 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. http://svn.python.org/view?view=rev&revision=83173 This change should be incorporated into MRAB's regex module in order to keep comparisons fair. -gps
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