mraleph

import 'dart:async';
import 'dart:html' as html;

stream() {
  final sc = new StreamController();

  spawn(ms, id) =>
    new Timer.periodic(new Duration(milliseconds: ms), (_) => sc.add(id));

  spawn(250, 1);

mraleph

--- Optimized code ---
kind = OPTIMIZED_FUNCTION
name = foo
stack_slots = 1
Instructions (size = 90)
0x48634f60     0  55             push ebp
0x48634f61     1  89e5           mov ebp,esp
0x48634f63     3  56             push esi
0x48634f64     4  57             push edi
0x48634f65     5  6a00           push 0x0

mraleph

                  ;;; <@80,#66> -------------------- B5 (loop header) --------------------
                  ;;; <@83,#68> compare-numeric-and-branch
0x598365b8   408  3bc3           cmp eax,ebx
0x598365ba   410  0f8d6f000000   jnl 527  (0x5983662f)
                  ;;; <@88,#75> -------------------- B7 --------------------
                  ;;; <@90,#77> stack-check
0x598365c0   416  3b251c691e09   cmp esp,[0x91e691c]
0x598365c6   422  0f8282000000   jc 558  (0x5983664e)
                  ;;; <@92,#79> check-non-smi
0x598365cc   428  f6c101         test_b cl,0x1

mraleph

$ cat test.js
function foo () { while (true) { } }
function bar () { return foo(); }
bar();
$ node test.js &
$ gdb attach $(pidof node)
0x00000bf778c63d5f in ?? ()
(gdb) b v8::internal::Runtime_StackGuard
Breakpoint 1 at 0x84a1f0
(gdb) print 'v8::V8::TerminateExecution'(0)

mraleph

var pi = (function () {
  var NTP = 25;
  var tp = [];

  tp[0] = 1.;
  for (var i = 1; i < NTP; i++) tp[i] = 2. * tp[i-1];

  function series(m, id) {
    var s = 0;
    var eps = 0.00000000000000001;

mraleph

--- Optimized code ---
kind = OPTIMIZED_FUNCTION
name = f138178145338511
stack_slots = 1
Instructions (size = 58)
0x5cacb8a0     0  55             push ebp
0x5cacb8a1     1  89e5           mov ebp,esp
0x5cacb8a3     3  56             push esi
0x5cacb8a4     4  57             push edi
0x5cacb8a5     5  6a00           push 0x0

mraleph

Making iteration faster in Array built-ins.

Lets imagine we have forEach method. The core loop of this method in V8 is implemented in JavaScript and looks like this:

for (var i = 0; i < length; i++) {
  if (i in array) {
    var element = array[i];
    %_CallFunction(receiver, element, i, array, f);
 }

mraleph

function BenchmarkRun() {
  // Benchmark.prototype.setup goes here
  obj = {
   "apples": true,
   "oranges": true,
   "pears": true,
    "pinapples": true,
    "grapes": true,
  }
  array = [

mraleph

function B1() {
  // Benchmark.prototype.setup goes here
  var str = '1.1'; 
  var start = new Date;
  for (...) { // do N iterations of test body
    str++;
  }
  var end = new Date;
};