Le Tue, 24 Nov 2009 08:58:40 -0800, Paul Boddie a écrit : > As you > point out, a lot of this RISC vs. CISC analysis (and inferences drawn > from Python bytecode analysis) is somewhat academic: the cost of the > JUMP_IF_FALSE instruction is likely to be minimal in the context of all > the activity going on to evaluate the bytecodes.
Sorry, I have trouble parsing your sentence. Do you mean bytecode interpretation overhead is minimal compared to the cost of actual useful work, or the contrary? (IMO both are wrong by the way) > I imagine that someone (or a number of people) must have profiled the > Python interpreter and shown how much time goes on the individual > bytecode implementations and how much goes on the interpreter's own > housekeeping activities. Well the one problem is that it's not easy to draw a line. Another problem is that it depends on the workload. If you are compressing large data or running expensive regular expressions the answer won't be the same as if you compute a Mandelbrot set in pure Python. One data point is that the "computed gotos" option in py3k generally makes the interpreter faster by ~15%. Another data point I've heard is that people who have tried a very crude form of Python-to-C compilation (generating the exact C code corresponding to a function or method, using Python's C API and preserving dynamicity without attempting to be clever) have apparently reached speedups of up to 50% (in other words, "twice as fast"). So you could say that the interpretation overhead is generally between 15% and 50%. -- http://mail.python.org/mailman/listinfo/python-list
