gistfile1.js

// This is modified version of benchmark from http://d.hatena.ne.jp/sumim/20110217/p1
//
// It is ~35% faster when I run it on the recent nodejs compiled for ia32 (V8 3.1.6).
//
// mraleph@whitestar|~/src/node/% ./node test.js                                                                              
// 0
// 3.509
// mraleph@whitestar|~/src/node/% ./node test-original.js                                                                     
// 0
// 5.344 
// 
// The secret behind the speedup is simple: I've given V8 a chance to inline calc into loop thus 
// removing boxing/unboxing of argument/return value.
//
// -- Vyacheslav Egorov
//

function Looping(){
   this.n0 = 0;
   this.calc = function(n){
      var n1 = this.n0 + (1 - 2*((n+2)%2));
      this.n0 = n;
      return n1;
   }
}

var l = new Looping();
var t1 = new Date();

// For some reason V8 does not consider calc for inlining if I declare loop as
//    function loop () { ... }
// I am still investigating why.
var loop = new Function("l", "var n = 1; for(var c=0;c<268435455;c++) n = l.calc(n); return n;");

var n = loop(l);

console.log("%s\n%s", n, (new Date() - t1) / 1000);