[events] benchmarking event emitter

benchmark/event_emitter.js

@@ -0,0 +1,138 @@
+var EventEmitter = require('events').EventEmitter,
+    assert       = require('assert');
+
+
+function noListeners(max) {
+  var ee = new EventEmitter();
+
+  for (var i = 0 ; i < max ; i ++) {
+    ee.emit('myevent');
+  }
+}
+
+function oneEventOneListener(max) {
+  var ee = new EventEmitter();
+  var eventCount = 0;
+
+  ee.on('myevent', function() {
+    eventCount ++;
+  });
+
+  for (var i = 0 ; i < max ; i ++) {
+    ee.emit('myevent');
+  }
+
+  assert.equal(eventCount, max);
+}
+
+function oneEventFourListeners(max) {
+  var ee = new EventEmitter();
+  var eventCount = 0;
+
+  for ( var l = 0 ; l < 4 ; l ++) {
+    ee.on('myevent', function() {
+      eventCount ++;
+    });
+  }
+
+  for (var i = 0 ; i < max ; i ++) {
+    ee.emit('myevent');
+  }
+
+  assert.equal(eventCount, max * 4);
+}
+
+function twoEventsTwoListeners(max) {
+  var ee = new EventEmitter();
+  max = max / 2;
+  var eventCount = 0;
+
+  for ( var l = 0 ; l < 2 ; l ++) {
+    ee.on('myevent' + l, function() {
+      eventCount ++;
+    });
+  }
+
+  for ( var j = 0 ; j < 2 ; j ++) {
+    for (var i = 0 ; i < max ; i ++) {
+      ee.emit('myevent' + j);
+    }
+  }
+
+  assert.equal(eventCount, max * 2);
+}
+
+function twoEventsFourListeners(max) {
+  var ee = new EventEmitter();
+  max = max / 2;
+  var eventCount = 0;
+
+  for ( var l = 0 ; l < 2 ; l ++) {
+    for ( var m = 0 ; m < 2 ; m ++) {
+      ee.on('myevent' + l, function() {
+        eventCount ++;
+      });
+    }
+  }
+
+  for ( var j = 0 ; j < 2 ; j ++) {
+    for (var i = 0 ; i < max ; i ++) {
+      ee.emit('myevent' + j);
+    }
+  }
+
+  assert.equal(eventCount, max * 4);
+}
+
+//
+// Test definitions
+//
+var tests = [
+  { name: 'no listeners'
+  , loop: 1e8
+  , fn: noListeners }
+, { name: '1 event, 1 listener'
+  , loop: 1e8
+  , fn: oneEventOneListener }
+, { name: '1 event, 4 listeners'
+  , loop: 1e8
+  , fn: oneEventFourListeners }
+, { name: '2 events, 2 listeners'
+  , loop: 1e8
+  , fn: twoEventsTwoListeners }
+, { name: '2 events, 4 listeners'
+  , loop: 1e8
+  , fn: twoEventsFourListeners }
+];
+
+function run(i) {
+
+  if (i >= tests.length) {
+    console.log('All done.');
+    return;
+  }
+
+  var test = tests[i];
+  var testFunc = test.fn;
+  var loop = test.loop;
+
+  var start = Date.now();
+
+  testFunc(loop);
+  var end = Date.now();
+  var diff = end - start;
+  var seconds = diff / 1000;
+  var rate = Math.round(loop / seconds);
+  console.log(test.name + ': Ellapsed: '  + seconds + 's. Rate: ' + rate + ' emits/sec.');
+  process.nextTick(function() {
+    run(i + 1);
+  });
+}
+
+if (process.argv[2]) {
+  tests = tests.filter(function(test) {
+    return test.name === process.argv[2];
+  });
+}
+
+run(0);