Paolo 'Blaisorblade' Giarrusso <p.giarru...@gmail.com> added the comment:
@Alexandre: > > So, can you try dropping the switch altogether, using always computed > > goto and seeing how does the resulting code get compiled? > Removing the switch won't be possible unless we change the semantic > EXTENDED_ARG. In addition, I doubt the improvement, if any, would worth > the increased complexity. OK, it's time that I post code to experiment with that - there is no need to break EXTENDED_ARG. And the point is to fight miscompilations. > Do you actually mean the time spent interpreting bytecodes compared to the time spent in the other parts of Python? If so, your figures are wrong for CPython on x86-64. It is about 50% just like on x86 (when running pybench). With the patch, this drops to 35% on x86-64 and to 45% on x86. More or less, I mean that, but I was making an example, and I made up reasonable figures. 70%, or even more, just for _dispatch_ (i.e. just for the mispredicted indirect jump), is valid for real-world Smalltalk interpreters for instance, or for the ones in "The Structure and Performance of Efficient Interpreters". But, when you say "intepreting opcodes", I do not know which part you refer to, if just the computed goto or for the whole code in the interpreter function. _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue4753> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
