2 files changed, 62 insertions, 56 deletions

diff --git a/cpu/simple_cpu/simple_cpu.cc b/cpu/simple_cpu/simple_cpu.cc
index 8b99a0105..77f0c41ed 100644
--- a/cpu/simple_cpu/simple_cpu.cc
+++ b/cpu/simple_cpu/simple_cpu.cc
@@ -216,6 +216,63 @@ SimpleCPU::execCtxStatusChg(int thread_num) {
         setStatus(Idle);
 }
 
+void
+SimpleCPU::setStatus(Status new_status)
+{
+    Status old_status = status();
+
+    // We should never even get here if the CPU has been switched out.
+    assert(old_status != SwitchedOut);
+
+    _status = new_status;
+
+    switch (status()) {
+      case IcacheMissStall:
+        assert(old_status == Running);
+        lastIcacheStall = curTick;
+        if (tickEvent.scheduled())
+            tickEvent.squash();
+        break;
+
+      case IcacheMissComplete:
+        assert(old_status == IcacheMissStall);
+        if (tickEvent.squashed())
+            tickEvent.reschedule(curTick + 1);
+        else if (!tickEvent.scheduled())
+            tickEvent.schedule(curTick + 1);
+        break;
+
+      case DcacheMissStall:
+        assert(old_status == Running);
+        lastDcacheStall = curTick;
+        if (tickEvent.scheduled())
+            tickEvent.squash();
+        break;
+
+      case Idle:
+        assert(old_status == Running);
+        notIdleFraction--;
+        if (tickEvent.scheduled())
+            tickEvent.squash();
+        break;
+
+      case Running:
+        assert(old_status == Idle ||
+               old_status == DcacheMissStall ||
+               old_status == IcacheMissComplete);
+        if (old_status == Idle)
+            notIdleFraction++;
+
+        if (tickEvent.squashed())
+            tickEvent.reschedule(curTick + 1);
+        else if (!tickEvent.scheduled())
+            tickEvent.schedule(curTick + 1);
+        break;
+
+      default:
+        panic("can't get here");
+    }
+}
 
 void
 SimpleCPU::regStats()
@@ -251,6 +308,7 @@ SimpleCPU::regStats()
         .prereq(dcacheStallCycles)
         ;
 
+    idleFraction = constant(1.0) - notIdleFraction;
     numInsts = Statistics::scalar(numInst) - Statistics::scalar(startNumInst);
     simInsts += numInsts;
 }
@@ -259,6 +317,7 @@ void
 SimpleCPU::resetStats()
 {
     startNumInst = numInst;
+    notIdleFraction = (_status != Idle);
 }
 
 void
diff --git a/cpu/simple_cpu/simple_cpu.hh b/cpu/simple_cpu/simple_cpu.hh
index b0189349f..666fe490b 100644
--- a/cpu/simple_cpu/simple_cpu.hh
+++ b/cpu/simple_cpu/simple_cpu.hh
@@ -174,61 +174,7 @@ class SimpleCPU : public BaseCPU
 
     virtual void execCtxStatusChg(int thread_num);
 
-    void setStatus(Status new_status) {
-        Status old_status = status();
-
-        // We should never even get here if the CPU has been switched out.
-        assert(old_status != SwitchedOut);
-
-        _status = new_status;
-
-        switch (status()) {
-          case IcacheMissStall:
-            assert(old_status == Running);
-            lastIcacheStall = curTick;
-            if (tickEvent.scheduled())
-                tickEvent.squash();
-            break;
-
-          case IcacheMissComplete:
-            assert(old_status == IcacheMissStall);
-            if (tickEvent.squashed())
-                tickEvent.reschedule(curTick + 1);
-            else if (!tickEvent.scheduled())
-                tickEvent.schedule(curTick + 1);
-            break;
-
-          case DcacheMissStall:
-            assert(old_status == Running);
-            lastDcacheStall = curTick;
-            if (tickEvent.scheduled())
-                tickEvent.squash();
-            break;
-
-          case Idle:
-            assert(old_status == Running);
-            idleFraction++;
-            if (tickEvent.scheduled())
-                tickEvent.squash();
-            break;
-
-          case Running:
-            assert(old_status == Idle ||
-                   old_status == DcacheMissStall ||
-                   old_status == IcacheMissComplete);
-            if (old_status == Idle && curTick != 0)
-                idleFraction--;
-
-            if (tickEvent.squashed())
-                tickEvent.reschedule(curTick + 1);
-            else if (!tickEvent.scheduled())
-                tickEvent.schedule(curTick + 1);
-            break;
-
-          default:
-            panic("can't get here");
-        }
-    }
+    void setStatus(Status new_status);
 
     // statistics
     virtual void regStats();
@@ -247,7 +193,8 @@ class SimpleCPU : public BaseCPU
     Counter startNumLoad;
 
     // number of idle cycles
-    Statistics::Average<> idleFraction;
+    Statistics::Average<> notIdleFraction;
+    Statistics::Formula idleFraction;
 
     // number of cycles stalled for I-cache misses
     Statistics::Scalar<> icacheStallCycles;