Comment by skohan
3 hours ago
The Linux kernel has to balance security and performance concerns, security probably being primary, so it makes sense to make the tradeoff for more safety with worse ergonomics for memory management.
If all you care about is performance, you're going to be fighting Rust's memory model for no reason.
> If all you care about is performance, you're going to be fighting Rust's memory model for no reason.
If you actually care about performance where you'd start is with measurements. What we see so much from C++ isn't measurements it is dogma. Things C++ forces on you must dogmatically be imagined as free without measuring them, things C++ does not have get treated as expensive, again without measuring so as to justify their absence.
For example, the unstable sort in C++ (std::sort) is typically implemented in a way which introduces Undefined Behaviour if your ordering isn't coherent either because you didn't realise that was mandatory or through some minor programming error. In contrast all of Rust's unstable sort implementations have been entirely safe even in the face of such mistakes.
And your dogma might tell you OK, but the C++ sort must be faster. That's why we're doing unsafe things, it must be faster. Except, nope, slower. Slower, but unsafe. Pointlessly worse. Only acceptable because of dogmatic belief.
With all due respect, are you sure you're not the one being dogmatic here?
90% of the code I write these days is Rust. It's a great tool, and the performance/safety balance, as well as general developer experience makes it well-suited to a wide variety of applications.
But in the past I've also built an ECS implementation. For that to optimize performance (and yes I did measure this) you want to do bulk memory allocations memory, pack bytes in order to minimize cache misses, and dispatch multiple threads to read and write concurrently over your memory pool. You can do all that in Rust, and people have, but it's a pain in the ass.
And for example, if I were working on a high-frequency trading application, where every millisecond of additional latency represents millions of dollars of lost revenue, I wouldn't waste my time fighting the burrow checker just so I can have a prettier program.
Rust is an amazing tool, but that doesn't mean it's the optimal tool for every job.