cpu: Accurately count idle cycles for simple cpu

Added a couple missing updates to the notIdleFraction stat. Without
these, it sometimes gives a (not) idle fraction that is greater than 1
or less than 0.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index ffd1c4d43..d29903c2f 100644
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -175,8 +175,10 @@ AtomicSimpleCPU::drainResume()
     if (thread->status() == ThreadContext::Active) {
         schedule(tickEvent, nextCycle());
         _status = BaseSimpleCPU::Running;
+        notIdleFraction = 1;
     } else {
         _status = BaseSimpleCPU::Idle;
+        notIdleFraction = 0;
     }
 
     system->totalNumInsts = 0;
@@ -244,7 +246,7 @@ AtomicSimpleCPU::activateContext(ThreadID thread_num, Cycles delay)
     assert(_status == Idle);
     assert(!tickEvent.scheduled());
 
-    notIdleFraction++;
+    notIdleFraction = 1;
     numCycles += ticksToCycles(thread->lastActivate - thread->lastSuspend);
 
     //Make sure ticks are still on multiples of cycles
@@ -271,7 +273,7 @@ AtomicSimpleCPU::suspendContext(ThreadID thread_num)
     if (tickEvent.scheduled())
         deschedule(tickEvent);
 
-    notIdleFraction--;
+    notIdleFraction = 0;
     _status = Idle;
 }