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Rust gets all your favourite kinds of atomics and barriers, exactly like C. Other things are indeed hard to get safe, which is why Rust has `unsafe`: it is poss

by dbaupp 10y ago

Rust gets all your favourite kinds of atomics and barriers, exactly like C. Other things are indeed hard to get safe, which is why Rust has `unsafe`: it is possible to use them, marking out the dangerous regions precisely, rather than the whole program being `unsafe` just because a few places need niche features. In any case, Rust is definitely not written with "I have one CPU" in mind. A slogan that is sometimes used for Rust is "safe. fast. concurrent.", and it's one of the headline features on the front page: http://rust-lang.org/ http://rust-lang.org/ . Rust's abstractions allows writing extremely high performance libraries like rayon, which, had better performance than even highly optimised C libraries like Cilk, in one benchmark I heard about. Building out that parallelism ecosystem takes time, so it does not seem particularly surprising that there are more (unsafe!) libraries for the 40-year-old language, than (safe!) libraries in the less-than-2-year-old one.

AstralStorm 10y ago
No, by one CPU i meant not a single core. I meant not having to manage different memory models and available access patterns. Or different ways of handling race conditions and alignments. You get to use unsafe almost exclusively in the internals of such access where it shouldn't be necessary if there are ways to specify more properties than just binary "safe" and "unsafe". It is extremely hard to prove such code correct in Rust.
- dbaupp 10y ago
  > I meant not having to manage different memory models and available access patterns The only way I can make this make sense, is having cross-platform abstraction around atomic orderings etc. (like the new C++11 std::atomics) that works on x86 and ARM and PowerPC etc. Rust has such a cross-platform abstraction, almost identical to C++11: https://doc.rust-lang.org/std/sync/atomic/index.html https://doc.rust-lang.org/std/sync/atomic/index.html Please be more specific about what exactly you mean if I am wrong.

by dbaupp 10y ago

AstralStorm 10y ago

No, by one CPU i meant not a single core. I meant not having to manage different memory models and available access patterns. Or different ways of handling race conditions and alignments. You get to use unsafe almost exclusively in the internals of such access where it shouldn't be necessary if there are ways to specify more properties than just binary "safe" and "unsafe". It is extremely hard to prove such code correct in Rust.

dbaupp 10y ago
> I meant not having to manage different memory models and available access patterns The only way I can make this make sense, is having cross-platform abstraction around atomic orderings etc. (like the new C++11 std::atomics) that works on x86 and ARM and PowerPC etc. Rust has such a cross-platform abstraction, almost identical to C++11: https://doc.rust-lang.org/std/sync/atomic/index.html https://doc.rust-lang.org/std/sync/atomic/index.html Please be more specific about what exactly you mean if I am wrong.