[Python-Dev] default of returning None hurts performance?

Antoine Pitrou solipsis at pitrou.net
Mon Aug 31 23:20:34 CEST 2009

Gregory P. Smith <greg <at> krypto.org> writes:
> food for thought as noticed by a coworker who has been profiling some hot code
to optimize a library...If a function does not have a return statement we return
None.  Ironically this makes the foo2 function below faster than the bar2
function at least as measured using bytecode size

I would be surprised if this "bytecode size" difference made a significant
difference in runtimes, given that function call cost should dwarf the cumulated
cost of POP_TOP and LOAD_CONST (two of the simplest opcodes you could find).

Did your coworker run any timings instead of basing his assumptions on bytecode



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