diff --git a/tools/profiler/nsProfiler.cpp b/tools/profiler/nsProfiler.cpp
index 8c4eabcbda6d..a9d56e6cb5aa 100644
--- a/tools/profiler/nsProfiler.cpp
+++ b/tools/profiler/nsProfiler.cpp
@@ -92,18 +92,18 @@ nsProfiler::IsActive(bool *aIsActive)
 }
 
 NS_IMETHODIMP
-nsProfiler::GetResponsivenessTimes(PRUint32 *aCount, float **aResult)
+nsProfiler::GetResponsivenessTimes(PRUint32 *aCount, double **aResult)
 {
   unsigned int len = 100;
-  const float* times = SAMPLER_GET_RESPONSIVENESS();
+  const double* times = SAMPLER_GET_RESPONSIVENESS();
   if (!times) {
     *aCount = 0;
     *aResult = nsnull;
     return NS_OK;
   }
 
-  float *fs = static_cast<float *>
-                       (nsMemory::Clone(times, len * sizeof(float)));
+  double *fs = static_cast<double *>
+                       (nsMemory::Clone(times, len * sizeof(double)));
 
   *aCount = len;
   *aResult = fs;
diff --git a/tools/profiler/public/nsIProfiler.idl b/tools/profiler/public/nsIProfiler.idl
index b683e4635772..f94710354793 100644
--- a/tools/profiler/public/nsIProfiler.idl
+++ b/tools/profiler/public/nsIProfiler.idl
@@ -35,13 +35,13 @@
 
 #include "nsISupports.idl"
 
-[scriptable, uuid(25db9b8e-8123-4de1-b36d-8bbbedf2cdf4)]
+[scriptable, uuid(97c34690-3ca8-4225-9f7d-bcdbb76f29ed)]
 interface nsIProfiler : nsISupports
 {
   void StartProfiler(in PRUint32 aInterval, in PRUint32 aEntries);
   void StopProfiler();
   string GetProfile();
   boolean IsActive();
-  void GetResponsivenessTimes(out PRUint32 aCount, [retval, array, size_is(aCount)] out float aResult);
+  void GetResponsivenessTimes(out PRUint32 aCount, [retval, array, size_is(aCount)] out double aResult);
 };
 
diff --git a/tools/profiler/sps/TableTicker.cpp b/tools/profiler/sps/TableTicker.cpp
index ee5126da6a3c..9ef99a99b319 100644
--- a/tools/profiler/sps/TableTicker.cpp
+++ b/tools/profiler/sps/TableTicker.cpp
@@ -116,7 +116,7 @@ public:
     , mTagName(aTagName)
   { }
 
-  ProfileEntry(char aTagName, float aTagFloat)
+  ProfileEntry(char aTagName, double aTagFloat)
     : mTagFloat(aTagFloat)
     , mLeafAddress(0)
     , mTagName(aTagName)
@@ -127,7 +127,7 @@ public:
 private:
   union {
     const char* mTagData;
-    float mTagFloat;
+    double mTagFloat;
     Address mTagAddress;
   };
   Address mLeafAddress;
@@ -538,8 +538,8 @@ bool mozilla_sampler_is_active()
   return t->IsActive();
 }
 
-float sResponsivenessTimes[100];
-float sCurrResponsiveness = 0.f;
+double sResponsivenessTimes[100];
+double sCurrResponsiveness = 0.f;
 unsigned int sResponsivenessLoc = 0;
 void mozilla_sampler_responsiveness(TimeStamp aTime)
 {
@@ -561,7 +561,7 @@ void mozilla_sampler_responsiveness(TimeStamp aTime)
   sLastTracerEvent = aTime;
 }
 
-const float* mozilla_sampler_get_responsiveness()
+const double* mozilla_sampler_get_responsiveness()
 {
   return sResponsivenessTimes;
 }
diff --git a/tools/profiler/sps/sps_sampler.h b/tools/profiler/sps/sps_sampler.h
index fb484dac7aea..19a899e71b1d 100644
--- a/tools/profiler/sps/sps_sampler.h
+++ b/tools/profiler/sps/sps_sampler.h
@@ -118,7 +118,7 @@ void mozilla_sampler_start(int aEntries, int aInterval);
 void mozilla_sampler_stop();
 bool mozilla_sampler_is_active();
 void mozilla_sampler_responsiveness(TimeStamp time);
-const float* mozilla_sampler_get_responsiveness();
+const double* mozilla_sampler_get_responsiveness();
 void mozilla_sampler_save();
 char* mozilla_sampler_get_profile();
 void mozilla_sampler_init();