diff --git a/dom/plugins/ipc/PluginModuleParent.cpp b/dom/plugins/ipc/PluginModuleParent.cpp
index 646913addc1b..994602bd9cc2 100644
--- a/dom/plugins/ipc/PluginModuleParent.cpp
+++ b/dom/plugins/ipc/PluginModuleParent.cpp
@@ -33,7 +33,6 @@
 #include "nsPrintfCString.h"
 
 #include "prsystem.h"
-#include "prdtoa.h"
 
 #ifdef XP_WIN
 #include "mozilla/widget/AudioSession.h"
@@ -111,7 +110,7 @@ PluginModuleParent::PluginModuleParent(const char* aFilePath)
     , mPlugin(NULL)
     , mTaskFactory(this)
 #ifdef XP_WIN
-    , mPluginCpuUsageOnHang()
+    , mPluginCpuUsageOnHang(-1)
 #endif
 #ifdef MOZ_CRASHREPORTER_INJECTOR
     , mFlashProcess1(0)
@@ -179,18 +178,11 @@ PluginModuleParent::WriteExtraDataForMinidump(AnnotationTable& notes)
         if (!hangID.IsEmpty()) {
             notes.Put(CS("HangID"), NS_ConvertUTF16toUTF8(hangID));
 #ifdef XP_WIN
-            if (mPluginCpuUsageOnHang.Length() > 0) {
+            if (mPluginCpuUsageOnHang >= 0) {
+              notes.Put(CS("PluginCpuUsage"), 
+                        nsPrintfCString("%.2f", mPluginCpuUsageOnHang));
               notes.Put(CS("NumberOfProcessors"),
                         nsPrintfCString("%d", PR_GetNumberOfProcessors()));
-
-              char buf[7];
-              PR_cnvtf(buf, NS_ARRAY_LENGTH(buf), 2, mPluginCpuUsageOnHang[0]);
-              notes.Put(CS("PluginCpuUsage"), CS(buf));
-
-              for (PRInt32 i=1; i<mPluginCpuUsageOnHang.Length(); ++i) {
-                PR_cnvtf(buf, NS_ARRAY_LENGTH(buf), 2, mPluginCpuUsageOnHang[i]);
-                notes.Put(nsPrintfCString("CpuUsageFlashProcess%d", i), CS(buf));
-              }
             }
 #endif
         }
@@ -235,53 +227,42 @@ FileTimeToUTC(const FILETIME& ftime)
   return li.QuadPart;
 }
 
-struct CpuUsageSamples
-{
-  PRUint64 sampleTimes[2];
-  PRUint64 cpuTimes[2];
-};
-
 bool 
-GetProcessCpuUsage(const InfallibleTArray<base::ProcessHandle>& processHandles, InfallibleTArray<float>& cpuUsage)
+GetProcessCpuUsage(const base::ProcessHandle& processHandle, float& cpuUsage)
 {
-  InfallibleTArray<CpuUsageSamples> samples(processHandles.Length());
   FILETIME creationTime, exitTime, kernelTime, userTime, currentTime;
   BOOL res;
 
-  for (PRUint32 i = 0; i < processHandles.Length(); ++i) {
-    ::GetSystemTimeAsFileTime(&currentTime);
-    res = ::GetProcessTimes(processHandles[i], &creationTime, &exitTime, &kernelTime, &userTime);
-    if (!res) {
-      NS_WARNING("failed to get process times");
-      return false;
-    }
-  
-    samples[i].sampleTimes[0] = FileTimeToUTC(currentTime);
-    samples[i].cpuTimes[0]    = FileTimeToUTC(kernelTime) + FileTimeToUTC(userTime);
+  ::GetSystemTimeAsFileTime(&currentTime);
+  res = ::GetProcessTimes(processHandle, &creationTime, &exitTime, &kernelTime, &userTime);
+  if (!res) {
+    NS_WARNING("failed to get process times");
+    return false;
   }
 
+  PRUint64 sampleTimes[2];
+  PRUint64 cpuTimes[2];
+  
+  sampleTimes[0] = FileTimeToUTC(currentTime);
+  cpuTimes[0]    = FileTimeToUTC(kernelTime) + FileTimeToUTC(userTime);
+
   // we already hung for a while, a little bit longer won't matter
   ::Sleep(50);
 
-  const PRInt32 numberOfProcessors = PR_GetNumberOfProcessors();
-
-  for (PRUint32 i = 0; i < processHandles.Length(); ++i) {
-    ::GetSystemTimeAsFileTime(&currentTime);
-    res = ::GetProcessTimes(processHandles[i], &creationTime, &exitTime, &kernelTime, &userTime);
-    if (!res) {
-      NS_WARNING("failed to get process times");
-      return false;
-    }
-
-    samples[i].sampleTimes[1] = FileTimeToUTC(currentTime);
-    samples[i].cpuTimes[1]    = FileTimeToUTC(kernelTime) + FileTimeToUTC(userTime);    
-
-    const PRUint64 deltaSampleTime = samples[i].sampleTimes[1] - samples[i].sampleTimes[0];
-    const PRUint64 deltaCpuTime    = samples[i].cpuTimes[1]    - samples[i].cpuTimes[0];
-    const float usage = 100.f * (float(deltaCpuTime) / deltaSampleTime) / numberOfProcessors;
-    cpuUsage.AppendElement(usage);
+  ::GetSystemTimeAsFileTime(&currentTime);
+  res = ::GetProcessTimes(processHandle, &creationTime, &exitTime, &kernelTime, &userTime);
+  if (!res) {
+    NS_WARNING("failed to get process times");
+    return false;
   }
 
+  sampleTimes[1] = FileTimeToUTC(currentTime);
+  cpuTimes[1]    = FileTimeToUTC(kernelTime) + FileTimeToUTC(userTime);    
+
+  const PRUint64 deltaSampleTime = sampleTimes[1] - sampleTimes[0];
+  const PRUint64 deltaCpuTime    = cpuTimes[1]    - cpuTimes[0];
+  cpuUsage = 100.f * (float(deltaCpuTime) / deltaSampleTime) / PR_GetNumberOfProcessors();
+
   return true;
 }
 
@@ -307,22 +288,9 @@ PluginModuleParent::ShouldContinueFromReplyTimeout()
 #endif
 
 #ifdef XP_WIN
-    // collect cpu usage for plugin processes
-
-    InfallibleTArray<base::ProcessHandle> processHandles;
-    InfallibleTArray<float> cpuUsage;
-    base::ProcessHandle handle;
-
-    processHandles.AppendElement(OtherProcess());
-    if (mFlashProcess1 && base::OpenProcessHandle(mFlashProcess1, &handle)) {
-      processHandles.AppendElement(handle);
-    }
-    if (mFlashProcess2 && base::OpenProcessHandle(mFlashProcess2, &handle)) {
-      processHandles.AppendElement(handle);
-    }
-
-    if (!GetProcessCpuUsage(processHandles, cpuUsage)) {
-      mPluginCpuUsageOnHang.Clear();
+    float cpuUsage;
+    if (GetProcessCpuUsage(OtherProcess(), cpuUsage)) {
+      mPluginCpuUsageOnHang = cpuUsage;
     }
 #endif
 
diff --git a/dom/plugins/ipc/PluginModuleParent.h b/dom/plugins/ipc/PluginModuleParent.h
index e6e89b6fe745..6e97665b784b 100644
--- a/dom/plugins/ipc/PluginModuleParent.h
+++ b/dom/plugins/ipc/PluginModuleParent.h
@@ -302,7 +302,7 @@ private:
     nsString mBrowserDumpID;
     nsString mHangID;
 #ifdef XP_WIN
-    InfallibleTArray<float> mPluginCpuUsageOnHang;
+    float mPluginCpuUsageOnHang;
 #endif
 
 #ifdef MOZ_X11
diff --git a/dom/plugins/test/mochitest/hang_test.js b/dom/plugins/test/mochitest/hang_test.js
index 47871b5bc72a..c260023963aa 100644
--- a/dom/plugins/test/mochitest/hang_test.js
+++ b/dom/plugins/test/mochitest/hang_test.js
@@ -79,7 +79,7 @@ var testObserver = {
     // check cpu usage field
     let extraData = parseKeyValuePairsFromFile(pluginExtraFile);
     ok("PluginCpuUsage" in extraData, "got extra field for plugin cpu usage");
-    let cpuUsage = parseFloat(extraData["PluginCpuUsage"]);
+    let cpuUsage = parseFloat(extraData["PluginCpuUsage"].replace(',', '.'));
     if (this.idleHang) {
       ok(cpuUsage == 0, "plugin cpu usage is 0%");
     } else {