Why This Python Performance Trick Doesn’t Matter Anymore

Comments

• JohnnyCanuck@lemmy.ca ⁨3⁩ ⁨weeks⁩ ago

  TLDR: 3.11 is twice as fast as 3.10 at doing global name lookups, so an old speedup hack of aliasing a global function locally isn’t needed.

  For example, when calling len() in a loop, going l=len, and calling l() in the loop was faster in 3.10. In 3.11, moreso in 3.13, it’s almost a wash.

  However, the author says this:

  Accessing functions through a module [e.g. math.sin()] or a deep attribute chain can still carry overhead. Creating a local alias or using “from module import name” continues to be effective in those situations.

  But when I look at the numbers, I would say 3.13 is pretty close to making it an unnecessary optimization in general. A little subjective on how you interpret the numbers.

  Great info, but this was like trying to use a recipe and reading the author’s life story to get there.

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  • squaresinger@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    Thanks for the summary!

    Yeah, in Python each . is a dictionary lookup. The cost of having a dynamic language where the compiler can do pretty much no optimizations (and yes, Python does have a compiler).

    In static languages these lookups can be collapsed to a single pointer address by the compiler.

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  • sugar_in_your_tea@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    I’m surprised about the module lookup thing, since I assumed it was just syntax sugar to do from … import …. We do the from syntax almost everywhere, but I’ve been replacing huge import blocks with a module import (e.g. constants) just to clean up the imports a bit and git conflicts.

    Looks like I’ll need to keep this in mind until we upgrade to 3.13.

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