diff --git a/src/system/kernel/scheduler/scheduler_thread.cpp b/src/system/kernel/scheduler/scheduler_thread.cpp
index 795fd9f730..d778b35c43 100644
--- a/src/system/kernel/scheduler/scheduler_thread.cpp
+++ b/src/system/kernel/scheduler/scheduler_thread.cpp
@@ -18,6 +18,7 @@ ThreadData::_InitBase()
 	fPriorityPenalty = 0;
 	fAdditionalPenalty = 0;
 	fEffectivePriority = GetPriority();
+	fCPUBound = false;
 
 	fTimeUsed = 0;
 	fStolenTime = 0;
diff --git a/src/system/kernel/scheduler/scheduler_thread.h b/src/system/kernel/scheduler/scheduler_thread.h
index 6e09314968..bfcaa59e77 100644
--- a/src/system/kernel/scheduler/scheduler_thread.h
+++ b/src/system/kernel/scheduler/scheduler_thread.h
@@ -50,7 +50,7 @@ public:
 
 	inline	int32		GetEffectivePriority() const;
 
-	inline	bool		IsCPUBound() const;
+	inline	bool		IsCPUBound() const	{ return fCPUBound; }
 
 	inline	void		CancelPenalty();
 	inline	bool		ShouldCancelPenalty() const;
@@ -116,6 +116,7 @@ private:
 
 			Thread*		fThread;
 
+			bool		fCPUBound;
 			int32		fPriorityPenalty;
 			int32		fAdditionalPenalty;
 
@@ -207,21 +208,15 @@ ThreadData::_IncreasePenalty()
 
 	int32 oldPenalty = fPriorityPenalty++;
 	const int kMinimalPriority = _GetMinimalPriority();
-	if (GetPriority() - oldPenalty <= kMinimalPriority)
+	if (GetPriority() - oldPenalty <= kMinimalPriority) {
 		fPriorityPenalty = oldPenalty;
+		fCPUBound = true;
+	}
 
 	_ComputeEffectivePriority();
 }
 
 
-inline bool
-ThreadData::IsCPUBound() const
-{
-	SCHEDULER_ENTER_FUNCTION();
-	return GetPriority() - fPriorityPenalty == _GetMinimalPriority();
-}
-
-
 inline void
 ThreadData::CancelPenalty()
 {
@@ -229,6 +224,7 @@ ThreadData::CancelPenalty()
 
 	int32 oldPenalty = fPriorityPenalty;
 	fPriorityPenalty = 0;
+	fCPUBound = false;
 
 	if (oldPenalty != 0) {
 		TRACE("cancelling thread %ld penalty\n", fThread->id);