When rust ≠ performance. a lesson in developer experience

When rust ≠ performance. a lesson in developer experience(suriya.cc)

37 points by suriya-ganesh 103 days ago | 24 comments

binhex 103 days ago |

> but because we have this data (file name, etc.) passed back and forth between different layers in the code. we were doing lots of .clone() and db.open() at different layers to fetch the same data. The interesting part for me was that, this change reduced our

Reduced your what? The article seems to be cut off.

taeric 103 days ago | |

I'm assuming it was going to say lines of code. It is highlighting that more was deleted than added.

larpingscholar 103 days ago | | |

I agree. Though the line count is meaningless as the vibe coded diff has pointless formatting and whitespace changes.

suriya-ganesh 103 days ago | |

ah! sorry. I meant to say, "the interesting part for me was that we removed code to improve performance."

notorandit 103 days ago |

Of course rust is not performance.

Rust is a programming language. Performance is a mix of programmer's ability, clever design and compiler optimizations.

jvanderbot 103 days ago | |

For a long time, Rust == performance because a _lot_ of people moved into Rust that had never really done programming with a concurrency-sane compiled programming language. For them, Rust was synonymous with performance!

Many supporting crates reinforced this. Rayon, Tokio (though not "performant", it was an improvement over naive impl), etc made jumping from hello world to parallel/concurrent execution pretty simple.

But I'm glad to see the downturn on that hype cycle.

koakuma-chan 103 days ago | | |

What is not performant about tokio? Do you know a better async runtime? I also heard tokio's "multi-thread" scheduler had some performance issues.

pointlessone 103 days ago |

This is extremely sparse on details.

bitexploder 103 days ago | |

Rust is a general purpose systems programming language. There are very few situations where you cannot attain C like performance with Rust. Skill issue, most likely.

koakuma-chan 103 days ago | |

It feels like a rage bait. It's clearly their own fault and has nothing to do with Rust.

LAC-Tech 103 days ago | | |

maybe Rustaceans shouldn't rage so easily?

kykat 103 days ago |

algorithm design and managing memory is something you have to think about regardless of what language you use, that should be obvious. Using rust doesn't guarantee correctness or performance, that should also be obvious.

Rust has features that make it easier to make correct and performant software, I think most programmers would agree?

Please stop this rust clickbait nonsense.

9rx 103 days ago | |

> Please stop this rust clickbait nonsense.

But then new content on HN would decline to nearly nothing.

themafia 103 days ago | |

> Using rust doesn't guarantee correctness or performance, that should also be obvious.

Judging from the most vocal segment of their community it's very much not obvious to them.

> make it easier

Define "easier." It's harder to make mistakes. I'm not sure this equates to developer "ease" in any way. In fact, if it's meant to be effective, it should be quite the opposite.

> rust clickbait nonsense.

It cuts both ways. There is a huge volume of "I switched to Rust and got 1% additional performance over C" posts here.

LAC-Tech 103 days ago |

I wonder to what extent the complexity of the rust language hurts performance. We all only have so much mental capacity, if much of it is spent on the various different intersections of rust's features, that reduces how much we can spend on making things fast.

(I like Rust btw)

nicoburns 103 days ago | |

The alternatives with the potential to be as fast (C, C++, D, zig) are more complex in this regard because they make memory safety and lifetime tracking something that you have to keep track of in your head. Rust's biggest win is removing that mental overhead while allowing you to achieve the same performance as those other languages.

Greduan 103 days ago | | |

Other languages remove lifetime tracking by making you track it in very limited spots. Instead of "for each individual object", you track it for "this particular kind of object in this part of my application".

I.e. don't need to keep track of the memory for each allocation in my HTTP request and make sure I clean it up before closing the connection, I can just allocate some memory _per request_, put stuff in it, and at the end it gets cleaned up, whether I used the memory or not.

Some languages have the idea of "memory allocators" as a native construct, so that you can actually start thinking about managing memory in more sensible terms than "everything individually", e.g. Odin lang.

LAC-Tech 103 days ago | | |

Rust also hides allocation, and both the standard library and community best practices encourage many smaller allocations, which makes it much harder to reason about performance characteristics of your code.

So what you say is definitely true if you do an allocation heavy, heap fragmenting, RAII style of programming. Which is the context Rust was born in, right? A kind of C++ app dev context where that was (is?) the prevailing meta.

You're also completely glossing over the incredible complexity you get in all thee weird intersection of rust features. And there are a LOT of features. Reasoning about those are not free from a mental overhead stand point.