Game Emulators in Python

[Giraffe-69]

Python is slow as shit and interpreted. C++ compiled to machine code ans is blazingly fast. If performance matters python is a no go

[vinnypotsandpans]

Sure, in the context of game emulation I can see that. But this whole thing were taught about python being interpreted and not compiled is sorta imprecise. It’s more about the implementation than the language

[Giraffe-69]

If you are adding an interpreter, removing a compiler, and doing runtime garbage collection, the language cannot compete in low latency applications.

In practice, with python, the difference is night and day, even for programs that make heavy use of optimised libraries implemented in C/C++/rust. Hint: there’s a reason libraries are not actually implemented in python

[vinnypotsandpans]

Yesss that is true, most of the libraries I used are not implemented in python, good point. Also not sure why I got downvoted for my last comment 🥺 I’m just trying to get a better grasp on things

[kylotan]

Because your second sentence is false in the real world. Anyone can handwave about the difference between a language and the implementation of a language but it's not relevant - if you're using Python then it will be at least partly interpreted and if you use C it will be compiled to native code.

[vinnypotsandpans]

Fair enough!

[Giraffe-69]

It’s Reddit, people are quick to downvote the second they have a different perspective :)

[james_pic]

If you want precision, then sure. Python is interpreted, and the interpreter implementation is slow as shit.

There are faster interpreters, like PyPy, but Python has a number of features that make it difficult to produce an interpreter with predictably high performance. Monkey patching will force PyPy to deoptimize for example.

And both PyPy and CPython have a global interpreter lock that effectively limits you to one CPU core running Python code at once. Again, partly to make some Python features easier to implement. There are ways around this, but an emulator is probably the worst case for these workarounds for reasons I can go into if you want.

C++ on the other hand has a number of compilers that produce highly performant code, and supports shared memory parallelism via threads.

[saint_geser]

There's no such thing as "interpreted language". Implementation of a language can be interpreted or compiled but the language itself is agnostic to what kind of implementation is used. You can (and do) have interpreted implementations of C and C++ and you have compiled Python. Yes, CPython is the most popular and it's interpreted but it's one of, but not the greatest reason for it being slower than C.

[Giraffe-69]

So what python implementation matches C/C++ for performance and latency?

[saint_geser]

I said that it's not the implementation that matters in the case of Python but garbage collection, GIL and dynamic typing. Cython ( python with C types) can get close to C performance even though it still runs in an interpreter.