[Python-Dev] default of returning None hurts performance? (original) (raw)

Scott Dial scott+python-dev at scottdial.com
Tue Sep 1 09:52:51 CEST 2009

Raymond Hettinger wrote:

I was just wondering if a bytecode for a superinstruction of the common sequence:

6 POPTOP 7 LOADCONST 0 (None) 10 RETURNVALUE might be worth it. [Collin Winter] I doubt it. You'd save a bit of stack manipulation, but since this will only appear at the end of a function, I'd be skeptical that this would make any macrobenchmarks (statistically) significantly faster. I concur with Collin. And since it appears only at the end of a function, the optimization doesn't help inner-loops in a function (where most of the time usually spent).

I fail to understand this crude logic. How often is the inner-loop really going to solely call C code? Any call to Python in an inner-loop is going to suffer this penalty on the order of the number of loop iterations)?

-Scott

-- Scott Dial scott at scottdial.com scodial at cs.indiana.edu

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