New submission from Łukasz Langa: I got a report that summing numbers is noticably slower on Python 3. This is easily reproducible:
$ time python2.7 -c "print sum(xrange(3, 10**9, 3)) + sum(xrange(5, 10**9, 5)) - sum(xrange(15, 10**9, 15))" 233333333166666668 real 0m6.165s user 0m6.100s sys 0m0.032s $ time python3.4 -c "print(sum(range(3, 10**9, 3)) + sum(range(5, 10**9, 5)) - sum(range(15, 10**9, 15)))" 233333333166666668 real 0m16.413s user 0m16.086s sys 0m0.089s I can't tell from initial poking what's the core issue here. Both examples produce equivalent bytecode, the builtin_sum() function is only noticably different in the fact that it uses PyLong_* across the board, including PyLong_AsLongAndOverlow. We'll need to profile this, which I didn't have time for yet. ---------- components: Interpreter Core messages: 242238 nosy: lukasz.langa, pitrou, rhettinger priority: normal severity: normal stage: needs patch status: open title: sum() several times slower on Python 3 type: performance versions: Python 3.4, Python 3.5 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue24076> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
