Skeptical of rewriting JavaScript tools in "faster" languages

We used to rewrite Python code in C++ "for performance". We stopped when the equivalent rewritten version appeared 3 times slower than the original.

The very notion of "fast and slow languages" is nonsense. A language is just an interface for a compiler, translator, or interpreter of some sort. A language is only steer wheel and pedals, not the whole car, so the whole arguments which one is faster is stupid.

In our case, AOT compilation backfired. We used (contractually had to) support older architectures and our Eigen built with meager SSE2 support couldn't possibly outrun Numpy built with AVX-512.

So we stopped rewriting. And then Numba (built on the same LLVM as clang) came up. And then not one but several AOT Python compilers. And now JIT compiler is in the standard Python.

And Numpy can't come anywhere close to the performance of my C++ code. Last time I benchmarked my CPU matrix multiplication algorithm, it went 27x faster than Numpy. Mostly because Numpy only used a single core. But this was a machine with eight cores. So my code went at least 3x faster. Moral of the story: C++ isn't something you can just foray into whenever Python is slow. It's the most complicated language there is, and the language itself is really just the tip of the iceberg of what we mean when we talk about C++. Do not underestimate the amount of devotion it takes get results out of C++ that are better than what high level libraries like Numpy can already provide you. https://justine.lol/c.jpg