4 ms·

I'm not sure about this specific case of Rust vs .NET, but the theoretical benefits of JITs never really seem to play out in practice, except for dynamic langua

I'm not sure about this specific case of Rust vs .NET, but the theoretical benefits of JITs never really seem to play out in practice, except for dynamic languages that can get really big improvements by using types speculatively. I think that one of the things that JIT proponents seem to miss is that JIT compilers have practical limits to the scope of analyses and optimizations that can be done...quick, single pass analyses, basic inclining, etc. An AOT isn't relying on competing with runtime resources to analyze and optimize code, and it can take a lot of time to do whatever it needs to. I've found that AOT with PGO is the performance holy grail for just about any use case.

int_19h 5y ago
There's one big benefit that JIT brings to the table that is not at all theoretical: it can devirtualize and inline across shared libraries. This doesn't matter if you link everything statically, of course, but that's not always desirable. (Another benefit is that it allows for generic virtual methods, but that's only indirectly a perf thing.)
hackerfromthefu 5y ago
With .NET it's been really interesting watching the journey to greater and greater performance - there's been so many performance optimizations that weren't implemented for 1-2 decades. So .. watch this space, possibly JIT performance will get improved more when they run out of lower hanging fruit.