Stefan Behnel <stefan...@behnel.de> added the comment:
Just FYI, I applied the same changes to the quicktions [1] module, a Cython compiled (and optimised) version of fractions.Fraction. [1] https://github.com/scoder/quicktions/ The loss in performance for small values is much higher there, almost 2x for the example given (compared to 10-20% for CPython): $ python3.8 -m timeit -r11 -s 'from fractions import Fraction as F' -s 'a=F(10,3)' -s 'b=F(6, 5)' 'a * b' 100000 loops, best of 11: 1.94 usec per loop Original: $ python3.8 -m timeit -r11 -s 'from quicktions import Fraction as F' -s 'a=F(10,3)' -s 'b=F(6, 5)' 'a * b' 1000000 loops, best of 11: 214 nsec per loop Patched: $ python3.8 -m timeit -r11 -s 'from quicktions import Fraction as F' -s 'a=F(10,3)' -s 'b=F(6, 5)' 'a * b' 500000 loops, best of 11: 391 nsec per loop For the larger values example, the gain is tremendous, OTOH: $ python3.8 -m timeit -r11 -s 'from fractions import Fraction as F' -s 'import random' -s 'n = [random.randint(1, 1000000) for _ in range(1000)]' -s 'd = [random.randint(1, 1000000) for _ in range(1000)]' -s 'a=list(map(lambda x: F(*x), zip(n, d)))' 'sum(a)' 2 loops, best of 11: 150 msec per loop Original: $ python3.8 -m timeit -r11 -s 'from quicktions import Fraction as F' -s 'import random' -s 'n = [random.randint(1, 1000000) for _ in range(1000)]' -s 'd = [random.randint(1, 1000000) for _ in range(1000)]' -s 'a=list(map(lambda x: F(*x), zip(n, d)))' 'sum(a)' 2 loops, best of 11: 135 msec per loop Patched: $ python3.8 -m timeit -r11 -s 'from quicktions import Fraction as F' -s 'import random' -s 'n = [random.randint(1, 1000000) for _ in range(1000)]' -s 'd = [random.randint(1, 1000000) for _ in range(1000)]' -s 'a=list(map(lambda x: F(*x), zip(n, d)))' 'sum(a)' 50 loops, best of 11: 9.65 msec per loop I'll have to see if the slowdown can be mitigated somehow. Interesting enough, the telco benchmark seems to benefit slightly from this: Original: $ python3.8 benchmark/telco_fractions.py -n 200 # avg 0.0952927148342 Patched: $ python3.8 benchmark/telco_fractions.py -n 200 # avg 0.0914235627651 ---------- nosy: +scoder _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue43420> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
