diff -r e3b7c2d371d8 -r 98add689157b src/base/statistics.hh
--- a/src/base/statistics.hh	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/base/statistics.hh	Sat Jul 10 02:21:48 2010 +0100
@@ -68,6 +68,7 @@
 #include "base/stats/visit.hh"
 #include "base/str.hh"
 #include "base/types.hh"
+#include "base/misc.hh"
 
 class Callback;
 
@@ -95,6 +96,8 @@
         visitor.visit(*static_cast<Base *>(this));
     }
     bool zero() const { return s.zero(); }
+    void backup() { s.backup(); }
+    void restore() { s.restore(); }
 };
 
 template <class Stat>
@@ -376,6 +379,24 @@
         for (off_type i = 0; i < size; ++i)
             self.data(i)->reset(info);
     }
+
+    void
+    backup()
+    {
+        Derived &self = this->self();
+        size_t size = self.size();
+        for (off_type i = 0; i < size; ++i)
+            self.data(i)->backup();
+    }
+
+    void
+    restore()
+    {
+        Derived &self = this->self();
+        size_t size = self.size();
+        for (off_type i = 0; i < size; ++i)
+            self.data(i)->restore();
+    }
 };
 
 template <class Derived, template <class> class InfoProxyType>
@@ -427,6 +448,8 @@
   private:
     /** The statistic value. */
     Counter data;
+    /** The backup value. */
+    Counter dataBackup;
 
   public:
     struct Params : public StorageParams {};
@@ -478,6 +501,16 @@
      * @return true if zero value
      */
     bool zero() const { return data == Counter(); }
+
+    /**
+     * Create a backup of the stat value.
+     */
+    void backup() { dataBackup = data; }
+
+    /**
+     * Restore the stat value from the backup.
+     */
+    void restore() { data = dataBackup; }
 };
 
 /**
@@ -492,12 +525,15 @@
   private:
     /** The current count. */
     Counter current;
-    /** The tick of the last reset */
-    Tick lastReset;
     /** The total count for all tick. */
     mutable Result total;
     /** The tick that current last changed. */
     mutable Tick last;
+    /** The total number of ticks counted. */
+    Tick totalTicks;
+    /** The backups. */
+    Counter backupCurrent;
+    Result backupTotal;
 
   public:
     struct Params : public StorageParams {};
@@ -507,7 +543,7 @@
      * Build and initializes this stat storage.
      */
     AvgStor(Info *info)
-        : current(0), lastReset(0), total(0), last(0)
+        : current(0), total(0), last(0), totalTicks(0)
     { }
 
     /**
@@ -519,6 +555,7 @@
     set(Counter val)
     {
         total += current * (curTick - last);
+        totalTicks += (curTick - last);
         last = curTick;
         current = val;
     }
@@ -549,7 +586,7 @@
     result() const
     {
         assert(last == curTick);
-        return (Result)(total + current) / (Result)(curTick - lastReset + 1);
+        return (Result)(total + current) / (Result)totalTicks;
     }
 
     /**
@@ -564,6 +601,7 @@
     prepare(Info *info)
     {
         total += current * (curTick - last);
+        totalTicks += curTick - last;
         last = curTick;
     }
 
@@ -574,10 +612,31 @@
     reset(Info *info)
     {
         total = 0.0;
+        totalTicks = 0;
         last = curTick;
-        lastReset = curTick;
     }
 
+    /**
+     * Backup stat value
+     */
+    void
+    backup()
+    {
+        prepare(NULL);
+        backupCurrent = current;
+        backupTotal = total;
+    }
+
+    /**
+     * Restore stat value
+     */
+    void
+    restore()
+    {
+        current = backupCurrent;
+        total = backupTotal;
+        last = curTick;
+    }
 };
 
 /**
@@ -697,6 +756,9 @@
 
     void reset() { data()->reset(this->info()); }
     void prepare() { data()->prepare(this->info()); }
+
+    void backup() { data()->backup(); }
+    void restore() { data()->restore(); }
 };
 
 class ProxyInfo : public ScalarInfo
@@ -710,6 +772,8 @@
     bool zero() const { return value() == 0; }
 
     void visit(Visit &visitor) { visitor.visit(*this); }
+    void backup() { }
+    void restore() { }
 };
 
 template <class T>
@@ -776,6 +840,8 @@
     bool check() const { return proxy != NULL; }
     void prepare() { }
     void reset() { }
+    void backup() { }
+    void restore() { }
 };
 
 //////////////////////////////////////////////////////////////////////
@@ -1016,6 +1082,20 @@
         return storage != NULL;
     }
 
+    void
+    backup()
+    {
+        for (off_type i = 0; i < size(); ++i)
+            data(i)->backup();
+    }
+
+    void
+    restore()
+    {
+        for (off_type i = 0; i < size(); ++i)
+            data(i)->restore();
+    }
+
   public:
     VectorBase()
         : storage(NULL)
@@ -1131,6 +1211,20 @@
     }
 
     size_type size() const { return len; }
+
+    void
+    backup()
+    {
+        for (off_type i = 0; i < size(); ++i)
+            data(i)->backup();
+    }
+
+    void
+    restore()
+    {
+        for (off_type i = 0; i < size(); ++i)
+            data(i)->restore();
+    }
 };
 
 template <class Derived, class Stor>
@@ -1257,6 +1351,22 @@
     {
         return storage != NULL;
     }
+
+    void
+    backup()
+    {
+        size_type size = this->size();
+        for (off_type i = 0; i < size; ++i)
+            data(i)->backup();
+    }
+
+    void
+    restore()
+    {
+        size_type size = this->size();
+        for (off_type i = 0; i < size; ++i)
+            data(i)->restore();
+    }
 };
 
 //////////////////////////////////////////////////////////////////////
@@ -1633,6 +1743,21 @@
     {
         data()->reset(this->info());
     }
+
+    /**
+     * Backup stat value.
+     */
+    void
+    backup()
+    {
+        warn_once("Not implemented backup / restore for distributions\n");
+    }
+
+    /**
+     * Restore stat value.
+     */
+    void
+    restore() { }
 };
 
 template <class Stat>
@@ -2484,6 +2609,9 @@
     bool zero() const;
 
     std::string str() const;
+
+    void backup() { }
+    void restore() { }
 };
 
 class FormulaNode : public Node
@@ -2761,6 +2889,16 @@
 
 std::list<Info *> &statsList();
 
+/**
+ * Backup all statistics
+ */
+void backup();
+
+/**
+ * Restore all statistics
+ */
+void restore();
+
 /* namespace Stats */ }
 
 #endif // __BASE_STATISTICS_HH__
diff -r e3b7c2d371d8 -r 98add689157b src/base/statistics.cc
--- a/src/base/statistics.cc	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/base/statistics.cc	Sat Jul 10 02:21:48 2010 +0100
@@ -377,4 +377,28 @@
     resetQueue.add(cb);
 }
 
+void
+backup()
+{
+    list<Info *>::iterator i = statsList().begin();
+    list<Info *>::iterator end = statsList().end();
+    while (i != end) {
+        Info *info = *i;
+        info->backup();
+        ++i;
+    }
+}
+
+void
+restore()
+{
+    list<Info *>::iterator i = statsList().begin();
+    list<Info *>::iterator end = statsList().end();
+    while (i != end) {
+        Info *info = *i;
+        info->restore();
+        ++i;
+    }
+}
+
 /* namespace Stats */ }
diff -r e3b7c2d371d8 -r 98add689157b src/base/stats/info.hh
--- a/src/base/stats/info.hh	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/base/stats/info.hh	Sat Jul 10 02:21:48 2010 +0100
@@ -133,6 +133,16 @@
     virtual void visit(Visit &visitor) = 0;
 
     /**
+     * Create a backup of the stat.
+     */
+    virtual void backup() = 0;
+
+    /**
+     * Restore the stat from the backup.
+     */
+    virtual void restore() = 0;
+
+    /**
      * Checks if the first stat's name is alphabetically less than the second.
      * This function breaks names up at periods and considers each subname
      * separately.
diff -r e3b7c2d371d8 -r 98add689157b src/python/m5/simulate.py
--- a/src/python/m5/simulate.py	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/python/m5/simulate.py	Sat Jul 10 02:21:48 2010 +0100
@@ -190,4 +190,10 @@
     for old_cpu, new_cpu in cpuList:
         new_cpu.takeOverFrom(old_cpu, connectMem)
 
+def backupStats():
+    stats.backup()
+
+def restoreStats():
+    stats.restore()
+
 from internal.core import disableAllListeners
diff -r e3b7c2d371d8 -r 98add689157b src/python/m5/stats.py
--- a/src/python/m5/stats.py	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/python/m5/stats.py	Sat Jul 10 02:21:48 2010 +0100
@@ -57,3 +57,9 @@
 
 def reset():
     internal.stats.reset()
+
+def backup():
+    internal.stats.backup()
+
+def restore():
+    internal.stats.restore()
diff -r e3b7c2d371d8 -r 98add689157b src/python/swig/stats.i
--- a/src/python/swig/stats.i	Sat Jul 10 02:21:10 2010 +0100
+++ b/src/python/swig/stats.i	Sat Jul 10 02:21:48 2010 +0100
@@ -56,6 +56,8 @@
 void prepare();
 void dump();
 void reset();
+void backup();
+void restore();
 
 std::list<Info *> &statsList();