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Comment by austin-cheney | Hacker News Reader

JavaScript executes 50x or more faster than Python. This has nothing to do with the event model. JavaScript compiles to a low level byte code in a VM at run time whereas Python is an interpreted language.

* https://benchmarksgame-team.pages.debian.net/benchmarksgame/...

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CPython compiles to a byte code, too and runs that (https://devguide.python.org/internals/interpreter/)

Any speed difference between the two is because of a combination of

- developers spending less effort on making it fast

- differences in the virtual machines instruction set

- differences in the languages that make one harder to run fast

I think/guess the first is the major reason, but the instruction set may matter, too. The last one has at most a minor impact.

A reason developers spend less time making the CPython interpreter faster is that you can relatively easily make ‘python’ even faster by making it call C code.

By "developers" you mean the core CPython developers here?

Because CPython itself is very slow, Java runs circles around it on most benchmarks you'll find such as this one[1] from Debian. If you observe the computation time taken, the order of magnitude of difference between Java and Python programs is just preposterous!

[1]: https://benchmarksgame-team.pages.debian.net/benchmarksgame/...

Node builds on top of V8, Chromium’s JS engine, which has JIT, which allows for some optimizations that aren’t as easy or obvious in a simple bytecode interpreter.

That’s exactly what I argue: the CPython developers choose not to spend time on a JIT (quite possibly because they didn’t have the resources to build a good one)

PyPy shows Python could have had a JIT (https://www.pypy.org/)

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