[Python-Dev] Tagged integers (original) (raw)

Jeff Epler jepler at unpythonic.net
Wed Jul 14 18:28:27 CEST 2004

I tried this back in 2002.

http://mail.python.org/pipermail/python-dev/2002-August/027685.html

Excerpt: [...] Subject: [Python-Dev] Performance (non)optimization: 31-bit ints in pointers || Performance results are mixed. A small program designed to test the | speed of all-integer arithmetic comes out faster by 14% (3.38 vs 2.90 | "user" time on my machine) but pystone comes out 5% slower (14124 vs 13358 | "pystones/second"). || I don't know if anybody's barked up this tree before, but I think | these results show that it's almost certainly not worth the effort to | incorporate this "performance" hack in Python. I'll keep my tree around | for awhile, in case anybody else wants to see it, but beware that it | still has serious issues even in the core: | >>> 0+0j | Traceback (most recent call last): | File "", line 1, in ? | TypeError: unsupported operand types for +: 'int' and 'complex' | >>> (0).class | Segmentation fault

Guido replied: | We used exactly this approach in ABC. I decided not to go with it | in Python, for two reasons that are essentially what you write up | here: (1) the changes are very pervasive (in ABC, we kept finding | places where we had pointer-manipulating code that had to be fixed to | deal with the small ints), and (2) it wasn't at all clear if it was a | performance win in the end (all the extra tests and special cases | may cost as much as you gain). http://mail.python.org/pipermail/python-dev/2002-August/027686.html

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