diff --git a/src/test/ReactDefaultPerf.js b/src/test/ReactDefaultPerf.js
index 46c27c4014..bed9d055f0 100644
--- a/src/test/ReactDefaultPerf.js
+++ b/src/test/ReactDefaultPerf.js
@@ -26,8 +26,12 @@ var ReactPerf = require('ReactPerf');
 
 var performanceNow = require('performanceNow');
 
+function roundFloat(val) {
+  return Math.floor(val * 100) / 100;
+}
+
 var ReactDefaultPerf = {
-  _allMeasurements: null, // last item in the list is the current one
+  _allMeasurements: [], // last item in the list is the current one
   _injected: false,
 
   start: function() {
@@ -35,7 +39,7 @@ var ReactDefaultPerf = {
       ReactPerf.injection.injectMeasure(ReactDefaultPerf.measure);
     }
 
-    ReactDefaultPerf._allMeasurements = [];
+    ReactDefaultPerf._allMeasurements.length = 0;
     ReactPerf.enableMeasure = true;
   },
 
@@ -53,8 +57,10 @@ var ReactDefaultPerf = {
     console.table(summary.map(function(item) {
       return {
         'Component class name': item.componentName,
-        'Exclusive time': item.exclusiveTime.toFixed(2) + ' ms',
-        'Inclusive time': item.inclusiveTime.toFixed(2) + ' ms'
+        'Total inclusive time (ms)': roundFloat(item.inclusive),
+        'Total exclusive time (ms)': roundFloat(item.exclusive),
+        'Exclusive time per instance (ms)': roundFloat(item.exclusive / item.count),
+        'Instances': item.count
       };
     }));
     console.log(
@@ -69,7 +75,8 @@ var ReactDefaultPerf = {
     console.table(summary.map(function(item) {
       return {
         'Owner > component': item.componentName,
-        'Inclusive time': item.inclusiveTime.toFixed(2) + ' ms'
+        'Inclusive time (ms)': roundFloat(item.time),
+        'Instances': item.count
       };
     }));
     console.log(
@@ -87,7 +94,8 @@ var ReactDefaultPerf = {
     console.table(summary.map(function(item) {
       return {
         'Owner > component': item.componentName,
-        'Wasted time': item.inclusiveTime.toFixed(2) + ' ms'
+        'Wasted time (ms)': item.time,
+        'Instances': item.count
       };
     }));
     console.log(
@@ -195,27 +203,32 @@ var ReactDefaultPerf = {
         }
         return rv;
       } else if (moduleName === 'ReactCompositeComponent' && (
+        fnName === 'mountComponent' ||
         fnName === 'updateComponent' || // TODO: receiveComponent()?
         fnName === '_renderValidatedComponent')) {
-        var isInclusive = fnName === 'updateComponent';
+
+        var rootNodeID = fnName === 'mountComponent' ?
+          args[0] :
+          this._rootNodeID;
+        var isRender = fnName === '_renderValidatedComponent';
         var entry = ReactDefaultPerf._allMeasurements[
           ReactDefaultPerf._allMeasurements.length - 1
         ];
-        if (isInclusive) {
-          // Since both updateComponent() and _renderValidatedComponent() are
-          // called for each render, only record the count for one of them.
-          entry.counts[this._rootNodeID] = entry.counts[this._rootNodeID] || 0;
-          entry.counts[this._rootNodeID] += 1;
+
+        if (isRender) {
+          entry.counts[rootNodeID] = entry.counts[rootNodeID] || 0;
+          entry.counts[rootNodeID] += 1;
         }
+
         start = performanceNow();
         rv = func.apply(this, args);
         totalTime = performanceNow() - start;
 
-        var typeOfLog = isInclusive ? entry.inclusive : entry.exclusive;
-        typeOfLog[this._rootNodeID] = typeOfLog[this._rootNodeID] || 0;
-        typeOfLog[this._rootNodeID] += totalTime;
+        var typeOfLog = isRender ? entry.exclusive : entry.inclusive;
+        typeOfLog[rootNodeID] = typeOfLog[rootNodeID] || 0;
+        typeOfLog[rootNodeID] += totalTime;
 
-        entry.displayNames[this._rootNodeID] = {
+        entry.displayNames[rootNodeID] = {
           current: this.constructor.displayName,
           owner: this._owner ? this._owner.constructor.displayName : '<root>'
         };
diff --git a/src/test/ReactDefaultPerfAnalysis.js b/src/test/ReactDefaultPerfAnalysis.js
index 4ad832d175..2dceaee1b3 100644
--- a/src/test/ReactDefaultPerfAnalysis.js
+++ b/src/test/ReactDefaultPerfAnalysis.js
@@ -77,8 +77,10 @@ function getExclusiveSummary(measurements) {
       displayName = measurement.displayNames[id].current;
 
       candidates[displayName] = candidates[displayName] || {
+        componentName: displayName,
         inclusive: 0,
-        exclusive: 0
+        exclusive: 0,
+        count: 0
       };
       if (measurement.exclusive[id]) {
         candidates[displayName].exclusive += measurement.exclusive[id];
@@ -86,32 +88,30 @@ function getExclusiveSummary(measurements) {
       if (measurement.inclusive[id]) {
         candidates[displayName].inclusive += measurement.inclusive[id];
       }
+      if (measurement.counts[id]) {
+        candidates[displayName].count += measurement.counts[id];
+      }
     }
   }
 
   // Now make a sorted array with the results.
   var arr = [];
   for (displayName in candidates) {
-    if (candidates[displayName].exclusiveTime < DONT_CARE_THRESHOLD) {
-      continue;
+    if (candidates[displayName].exclusive >= DONT_CARE_THRESHOLD) {
+      arr.push(candidates[displayName]);
     }
-    arr.push({
-      componentName: displayName,
-      exclusiveTime: candidates[displayName].exclusive,
-      inclusiveTime: candidates[displayName].inclusive
-    });
   }
 
   arr.sort(function(a, b) {
-    return b.exclusiveTime - a.exclusiveTime;
+    return b.exclusive - a.exclusive;
   });
 
   return arr;
 }
 
 function getInclusiveSummary(measurements, onlyClean) {
-  var inclusiveTimes = {};
-  var displayName;
+  var candidates = {};
+  var inclusiveKey;
 
   for (var i = 0; i < measurements.length; i++) {
     var measurement = measurements[i];
@@ -127,35 +127,38 @@ function getInclusiveSummary(measurements, onlyClean) {
         continue;
       }
 
-      displayName = measurement.displayNames[id];
+      var displayName = measurement.displayNames[id];
 
       // Inclusive time is not useful for many components without knowing where
       // they are instantiated. So we aggregate inclusive time with both the
       // owner and current displayName as the key.
-      var inclusiveKey = displayName.owner + ' > ' + displayName.current;
+      inclusiveKey = displayName.owner + ' > ' + displayName.current;
 
-      inclusiveTimes[inclusiveKey] = inclusiveTimes[inclusiveKey] || 0;
+      candidates[inclusiveKey] = candidates[inclusiveKey] || {
+        componentName: inclusiveKey,
+        time: 0,
+        count: 0
+      };
 
       if (measurement.inclusive[id]) {
-        inclusiveTimes[inclusiveKey] += measurement.inclusive[id];
+        candidates[inclusiveKey].time += measurement.inclusive[id];
+      }
+      if (measurement.counts[id]) {
+        candidates[inclusiveKey].count += measurement.counts[id];
       }
     }
   }
 
   // Now make a sorted array with the results.
   var arr = [];
-  for (displayName in inclusiveTimes) {
-    if (inclusiveTimes[displayName] < DONT_CARE_THRESHOLD) {
-      continue;
+  for (inclusiveKey in candidates) {
+    if (candidates[inclusiveKey].time >= DONT_CARE_THRESHOLD) {
+      arr.push(candidates[inclusiveKey]);
     }
-    arr.push({
-      componentName: displayName,
-      inclusiveTime: inclusiveTimes[displayName]
-    });
   }
 
   arr.sort(function(a, b) {
-    return b.inclusiveTime - a.inclusiveTime;
+    return b.time - a.time;
   });
 
   return arr;