Marc-Andre Lemburg <m...@egenix.com> added the comment: STINNER Victor wrote: > > I tried the collision counting with a low number of collisions: > ... no false positives with a limit of 50 collisions ...
Thanks for running those tests. Looks like a limit lower than 1000 would already do just fine. Some timings showing how long it would take to hit a limit: # 100 python2.7 -m timeit -n 100 "dict((x*(2**64 - 1), 1) for x in xrange(1, 100))" 100 loops, best of 3: 297 usec per loop # 250 python2.7 -m timeit -n 100 "dict((x*(2**64 - 1), 1) for x in xrange(1, 250))" 100 loops, best of 3: 1.46 msec per loop # 500 python2.7 -m timeit -n 100 "dict((x*(2**64 - 1), 1) for x in xrange(1, 500))" 100 loops, best of 3: 5.73 msec per loop # 750 python2.7 -m timeit -n 100 "dict((x*(2**64 - 1), 1) for x in xrange(1, 750))" 100 loops, best of 3: 12.7 msec per loop # 1000 python2.7 -m timeit -n 100 "dict((x*(2**64 - 1), 1) for x in xrange(1, 1000))" 100 loops, best of 3: 22.4 msec per loop These timings have to matched against the size of the payload needed to trigger those limits. In any case, the limit needs to be configurable like the hash seed in the randomization patch. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue13703> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
