We are rebuilding a core infrastructure system from unmaintained python (it's from before our company was bought and everyone left) to java. It's nothing interesting, standard ML infrastructure fare. A straightforward, uncareful, like weekend implementation in java was over ten times faster.

The reason is very simple: Python takes longer for a few function calls than Java takes to do everything. There's nothing I can do to fix that.

I wrote a portion of code that just takes a list of 170ish simple functions and run them, and they are such that it should be parallelizable, but I was rushing and just slapped the boring serialized version into place to get things working. I'll fix it when we need to be faster I thought.

The entire thing runs in a couple nanoseconds.

So much of our industry is writing godawful interpreted code and then having to do crazy engineering to get stupid interpreted languages to do a little faster.

Oh, and this was before I fixed it so the code didn't rebuild a constant regex pattern 100k times per task.

But our computers are so stupidly fast. It's so refreshing to be able to just write code and it runs as fast as computers run. The naive, trivial to read and understand code just works. I don't need a PhD to write it, understand it, or come up with it.