2016-11-02 15:20 GMT+01:00 Armin Rigo <armin.r...@gmail.com>: > Is that really the kind of examples you want to put forward?
I am not a big fan of timeit, but we must use it sometimes to micro-optimizations in CPython to check if an optimize really makes CPython faster or not. I am only trying to enhance timeit. Understanding results require to understand how the statements are executed. > This example means "compare CPython where the data cache gets extra pressure > from reading a strangely large code object, I wrote --duplicate option to benchmark "x+y" with "x=1; y=2". I know, it's an extreme and stupid benchmark, but many people spend a lot of time on trying to optimize this in Python/ceval.c: https://bugs.python.org/issue21955 I tried multiple values of --duplicate when benchmarking x+y, and x+y seems "faster" when using a larger --duplicate value. I understand that the cost of the outer loop is higher than the cost of "reading a strangely large code object". I provide a tool and I try to document how to use it. But it's hard to prevent users to use it for stupid things. For example, recently I spent time trying to optimize bytes%args in Python 3 after reading an article, but then I realized that the Python 2 benchmark was meaningless: https://atleastfornow.net/blog/not-all-bytes/ def bytes_plus(): b"hi" + b" " + b"there" ... benchmark(bytes_plus) ... bytes_plus() is optimized by the _compiler_, so the benchmark measure the cost of LOAD_CONST :-) The issue was not the tool but the usage of the tool :-D Victor _______________________________________________ Speed mailing list Speed@python.org https://mail.python.org/mailman/listinfo/speed
