5 ms·

But isn't the point that sufficiently smart compilers are supposed to compile to faster than C?

barrkel 8y ago
Are you being facetious? :) "Sufficiently smart compiler" - http://wiki.c2.com/?SufficientlySmartCompiler http://wiki.c2.com/?SufficientlySmartCompiler Don't get me wrong, I like C - especially on small problems. I don't get the feeling that I'm creating something flexible with C, though, it's very much bespoke and tailored. I get involved in micromanagement of fine details. This is OK for a small problem, but extremely aggravating for a big problem. As soon as I want higher level abstractions, and start building structs of function pointers and whatnot, I just shake my head - I'd rather write a parser and corresponding text generator than manually compile that into C. C++ has been hobbled by the concept of a sufficiently smart compiler. It's so afraid of introducing abstractions that aren't cost-free, it tries to make them all optional, and the resulting explosion in feature combination means some combinations don't work well together, and then every big C++ project has to decide which set of features they'll adopt, and which ones they won't. Give me the freedom to think closer to the problem, and even if the abstractions have some costs, and even if the compilers aren't quite sufficiently smart, the chances are I'll come up with algorithm improvements that meet speed and space requirements and let me move on to the next problem much sooner. Agility trumps hyper-optimization.
- jstimpfle 8y ago
  According to some people, the problem is the data. C is a nice language for dealing with plain data. Just today I rewrote my own streams abstraction, because libc sucks and I want to support my own printf style functions and my own custom streams (for example dynamically memory allocating streams. fopencookie() is not portable). I think that streams are one of the most abstract and most useful abstractions. It went pretty good. Making a few vtables explicitly in a few places is not that terrible.
maxxxxx 8y ago
That has been the dream for a long time. When Java introduced JIT (Hotspot?) a lot of people claimed that Java was faster than C. Lately people are telling me that JavaScript "can" run faster than C. Usually they present some well written code in their favorite language and then compare it to horribly written C. Usually I tell them that most likely the runtime of their language is written in C so you can always do as well in C.
- saagarjha 8y ago
  > Usually I tell them that most likely the runtime of their language is written in C so you can always do as well in C. The point is that with a JIT the runtime is executing as little as possible, with the rest being dynamically optimized machine code. So this isn’t really a fair thing to say…
  - gameswithgo 8y ago
    I've never seen in practice any jit do better than hand tuned AOT compiled code.
    - saagarjha 8y ago
      It's rare, but it can happen occasionally. A just-in-time compiler has access to tracing and profiling that a ahead-of-time compiler may not, which means that it can do things like inline a virtual method call that is actually monomorphic at runtime.
      - maxxxxx 8y ago
        “occasionally” That’s the keyword here.
        saagarjha 8y ago
        I was responding to a comment that had the word "never" in it.
    - 8y ago

Are you being facetious? :) "Sufficiently smart compiler" - http://wiki.c2.com/?SufficientlySmartCompiler http://wiki.c2.com/?SufficientlySmartCompiler Don't get me wrong, I like C - especially on small problems. I don't get the feeling that I'm creating something flexible with C, though, it's very much bespoke and tailored. I get involved in micromanagement of fine details. This is OK for a small problem, but extremely aggravating for a big problem. As soon as I want higher level abstractions, and start building structs of function pointers and whatnot, I just shake my head - I'd rather write a parser and corresponding text generator than manually compile that into C. C++ has been hobbled by the concept of a sufficiently smart compiler. It's so afraid of introducing abstractions that aren't cost-free, it tries to make them all optional, and the resulting explosion in feature combination means some combinations don't work well together, and then every big C++ project has to decide which set of features they'll adopt, and which ones they won't. Give me the freedom to think closer to the problem, and even if the abstractions have some costs, and even if the compilers aren't quite sufficiently smart, the chances are I'll come up with algorithm improvements that meet speed and space requirements and let me move on to the next problem much sooner. Agility trumps hyper-optimization.

jstimpfle 8y ago
According to some people, the problem is the data. C is a nice language for dealing with plain data. Just today I rewrote my own streams abstraction, because libc sucks and I want to support my own printf style functions and my own custom streams (for example dynamically memory allocating streams. fopencookie() is not portable). I think that streams are one of the most abstract and most useful abstractions. It went pretty good. Making a few vtables explicitly in a few places is not that terrible.

maxxxxx 8y ago

That has been the dream for a long time. When Java introduced JIT (Hotspot?) a lot of people claimed that Java was faster than C. Lately people are telling me that JavaScript "can" run faster than C. Usually they present some well written code in their favorite language and then compare it to horribly written C. Usually I tell them that most likely the runtime of their language is written in C so you can always do as well in C.

saagarjha 8y ago
> Usually I tell them that most likely the runtime of their language is written in C so you can always do as well in C. The point is that with a JIT the runtime is executing as little as possible, with the rest being dynamically optimized machine code. So this isn’t really a fair thing to say…
- gameswithgo 8y ago
  I've never seen in practice any jit do better than hand tuned AOT compiled code.
  - saagarjha 8y ago
    It's rare, but it can happen occasionally. A just-in-time compiler has access to tracing and profiling that a ahead-of-time compiler may not, which means that it can do things like inline a virtual method call that is actually monomorphic at runtime.
    - maxxxxx 8y ago
      “occasionally” That’s the keyword here.
      - saagarjha 8y ago
        I was responding to a comment that had the word "never" in it.
  - 8y ago