Kristján Valur Jónsson <krist...@ccpgames.com> added the comment: Yes, there is a measurable performance decrease in pybench arithmetic tests.
Integers don't fall out of arithmetic that often, true. But integral floats are incredibly common in tabular data. In a game such as Eve Online, configuration data contains a lot of 0.0, 1.0, -1.0 and so on. This patch saved us many megabytes on the server. I can check again... >>> [sys.getrefcount(float(i)) for i in range(-10, 11)] [777, 4, 38, 9, 215, 691, 627, 185, 98, 603, 73180, 62111, 8326, 6225, 6357, 11737, 2906, 1393, 3142, 1145, 5601] >>> sum([sys.getrefcount(float(i)) for i in range(-10, 11)]) 185340 >>> This is on an idle server. A server with lots of stuff going on will have this: [16715, 184, 1477, 34, 1505, 27102, 3878, 1344, 6248, 974, 595889, 313062, 124072, 120054, 65585, 138667, 13265, 2499, 15677, 3175, 24821] >>> sum([sys.getrefcount(float(i)) for i in range(-10, 11)]) 1465155 About half of the interned floats are 0.0 On a 64 bit machine with each float taking 24 bytes, this is 35mb net. An alternative could be to add a function for manual intering of floating point data, which one can use e.g. when reading tabular data. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue14381> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
