Why is processing a sorted array not faster than an unsorted array in Python?

Question

In this post Why is processing a sorted array faster than random array, it says that branch predicton is the reason of the performance boost in sorted arrays.

But I just

Answer 1

I may be wrong, but I see a fundamental difference between the linked question and your example: Python interprets bytecode, C++ compiles to native code.

In the C++ code that if translates directly to a cmp/jl sequence, that can be considered by the CPU branch predictor as a single "prediction spot", specific to that cycle.

In Python that comparison is actually several function calls, so there's (1) more overhead and (2) I suppose the code that performs that comparison is a function into the interpreter used for every other integer comparison - so it's a "prediction spot" not specific to the current block, which gives the branch predictor a much harder time to guess correctly.

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Edit: also, as outlined in this paper, there are way more indirect branches inside an interpreter, so such an optimization in your Python code would probably be buried anyway by the branch mispredictions in the interpreter itself.