*** old/src/share/vm/gc_implementation/shared/gcUtil.hpp	Fri May  4 11:52:03 2012
--- new/src/share/vm/gc_implementation/shared/gcUtil.hpp	Fri May  4 11:52:03 2012

*** 48,78 ****
--- 48,89 ----
    float            _average;        // The last computed average
    unsigned         _sample_count;   // How often we've sampled this average
    unsigned         _weight;         // The weight used to smooth the averages
                                      //   A higher weight favors the most
                                      //   recent data.
+   bool             _is_old;         // Has enough historical data
+ 
+   const static unsigned OLD_THRESHOLD = 100;
  
   protected:
    float            _last_sample;    // The last value sampled.
  
!   void  increment_count()       { _sample_count++;       }
+     _sample_count++;
+     if (!_is_old && _sample_count > OLD_THRESHOLD) {
+       _is_old = true;
+     }
+   }
+ 
    void  set_average(float avg)  { _average = avg;        }
  
    // Helper function, computes an adaptive weighted average
    // given a sample and the last average
    float compute_adaptive_average(float new_sample, float average);
  
   public:
    // Input weight must be between 0 and 100
    AdaptiveWeightedAverage(unsigned weight, float avg = 0.0) :
!     _average(avg), _sample_count(0), _weight(weight), _last_sample(0.0) {
!     _average(avg), _sample_count(0), _weight(weight), _last_sample(0.0),
+     _is_old(false) {
    }
  
    void clear() {
      _average = 0;
      _sample_count = 0;
      _last_sample = 0;
+     _is_old = false;
    }
  
    // Useful for modifying static structures after startup.
    void  modify(size_t avg, unsigned wt, bool force = false)  {
      assert(force, "Are you sure you want to call this?");

*** 83,92 ****
--- 94,104 ----
    // Accessors
    float    average() const       { return _average;       }
    unsigned weight()  const       { return _weight;        }
    unsigned count()   const       { return _sample_count;  }
    float    last_sample() const   { return _last_sample;   }
+   bool     is_old()  const       { return _is_old;        }
  
    // Update data with a new sample.
    void sample(float new_sample);
  
    static inline float exp_avg(float avg, float sample,