A simple exponential time shootout between C, Java and Swift

Fib.txt

/* 
  Algorithm is exponential - very bad.  It is just meant to exercise the CPU a bit and
  to see what happens with different languages.  Not representative of real code.
  Interesting that Java beats C, thanks to HotSpot. I expected Swift to be as fast as C
  at least.  I also expected the compiled Swift to be faster than when run as a script.
  A bit disappointed, but more time needed to see where the bottlenecks are.  Plus I 
  need to run some real code for benchmarking.
  
  Update: swiftc -O improved the speed quite a bit to be about the same speed as Java
  
  Disclaimer: Whilst I know Java pretty well, the last time I wrote a C program was
  probably in 1992.  I couldn't even remember how to printf() a long!  And I also 
  don't know Swift very well yet.  I'm hoping that someone can show me what I'm doing
  wrong that the compiled Swift code runs slower than swift < fib.swift.
  
  Disclaimer2: Yes, I know we should run the code several times to get an average speed, etc. :-)
  
  Times on my machine MacBook Pro (Retina, 15-inch, Late 2013), 2.6 GHz Intel Core i7
  
  Java - user 0m7.981s
  Swift 3.0 compiled with -O - user 0m8.303s
  C with -O - user 0m10.437s
  C - user 0m12.649s
  Swift 3.0 uncompiled - user 0m14.170s
  Swift 3.0 compiled - user 0m22.140s
*/

/* Java */
public class Fib {
  public static void main(String... args) {
    for(int n=10; n <= 44; n++) {
      System.out.printf("fib(%d)=%d%n", n, fib(n));
    }
  }

  public static long fib(int n) {
    if (n < 2) return n;
    return fib(n-1) + fib(n-2);
  }
}

/* C */
#include<stdio.h>

unsigned long fib(int n) {
  if (n < 2) return n;
  return fib(n-1) + fib(n-2);
}

int main() {
  for(int n=10; n <= 44; n++) {
    printf("fib(%d)=%lu\n", n, fib(n));
  }
}

/* Swift 3.0 */
func fib(_ n : Int) -> Int {
  if n < 2 {
    return n
  } else {
    return fib(n-1) + fib(n-2)
  }
}

for n in 10...44 {
  print("fib(\(n))=\(fib(n))") 
} 

And if you have a few mSecs to spend, impress your boss with:

Clear["Global`fib"];
phi := (1 + Sqrt[5])/2;
fib[n_] := fib[n] = Simplify[(phi^n - (1 - phi)^n) /Sqrt[5]];
Timing[Table[{n, fib[n]}, {n, 1, 44}]]

but gcc -O3 makes the C version 25% faster than the Java version on my machine. Linux with everything updated Intel(R) Core(TM) i7-3960X CPU @ 3.30GHz.

-O3 seems fair since you allow hotspot to do all sorts of magic... ;)

What if the Java test uses boxed types (to take it closer to Swift)?

What if you ran the Java one using -server?