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Huh. I expected two main advantages on Rust's side: usable multithreading (as mentioned) and stack allocation. For the latter, the ownership model makes it poss

by sfink 9mo ago

Huh. I expected two main advantages on Rust's side: usable multithreading (as mentioned) and stack allocation. For the latter, the ownership model makes it possible to stack-allocate things that you wouldn't dare put on the stack in either C or C++, thus saving malloc and free time as well as second-order effects from avoiding fragmentation. Does Rust not do this for subtle reasons that I'm missing, or does it just not matter as much as I'd expect it to?

steveklabnik 9mo ago
Both of those things are important, sure. I wanted this post to be talking about the higher level conceptual question, and then using interesting examples to tease out various aspects of that discussion, more than "here's what I think are the biggest differences between the two." I think these two things are also things people would argue about a lot. It's hard to talk about them in a concrete sense of things, rather than just "I feel like code usually does X".
- sfink 9mo ago
  Right, sorry, I didn't mean to imply that you should have covered stack allocation in your post. I think your post covers the right material to make its point. This is more of a side comment about a different question, perhaps "ok fine, but then what are the language differences that could be performance-relevant for one language or the other, even if (as you say) they don't lead to a yes/no answer for your original question?"
  - steveklabnik 9mo ago
    The ones I think, personally: 1. crates.io makes it easy to use complex data structures. Basically this argument https://bcantrill.dtrace.org/2018/09/28/the-relative-performance-of-c-and-rust/ https://bcantrill.dtrace.org/2018/09/28/the-relative-perform... 2. Rust's safety guarantees making it easier to maintain more dangerous things over time. 3. On the C side, there's a lot more cultural understanding overall of how to use the language to get good performance results 4. It might be easier to find people who are experienced in heavily optimizing C code as opposed to Rust code.

by sfink 9mo ago

steveklabnik 9mo ago

Both of those things are important, sure. I wanted this post to be talking about the higher level conceptual question, and then using interesting examples to tease out various aspects of that discussion, more than "here's what I think are the biggest differences between the two." I think these two things are also things people would argue about a lot. It's hard to talk about them in a concrete sense of things, rather than just "I feel like code usually does X".

sfink 9mo ago
Right, sorry, I didn't mean to imply that you should have covered stack allocation in your post. I think your post covers the right material to make its point. This is more of a side comment about a different question, perhaps "ok fine, but then what are the language differences that could be performance-relevant for one language or the other, even if (as you say) they don't lead to a yes/no answer for your original question?"
- steveklabnik 9mo ago
  The ones I think, personally: 1. crates.io makes it easy to use complex data structures. Basically this argument https://bcantrill.dtrace.org/2018/09/28/the-relative-performance-of-c-and-rust/ https://bcantrill.dtrace.org/2018/09/28/the-relative-perform... 2. Rust's safety guarantees making it easier to maintain more dangerous things over time. 3. On the C side, there's a lot more cultural understanding overall of how to use the language to get good performance results 4. It might be easier to find people who are experienced in heavily optimizing C code as opposed to Rust code.