diff --git a/src/system/kernel/scheduler/low_latency.cpp b/src/system/kernel/scheduler/low_latency.cpp
index 832b7ab1d3..a3eb28be4a 100644
--- a/src/system/kernel/scheduler/low_latency.cpp
+++ b/src/system/kernel/scheduler/low_latency.cpp
@@ -63,7 +63,7 @@ choose_core(Thread* thread)
 {
 	CoreEntry* entry = NULL;
 
-	SpinLocker locker(gIdlePackageLock);
+	ReadSpinLocker locker(gIdlePackageLock);
 	// wake new package
 	PackageEntry* package = gIdlePackageList->Last();
 	if (package == NULL) {
@@ -73,7 +73,7 @@ choose_core(Thread* thread)
 	locker.Unlock();
 
 	if (package != NULL) {
-		SpinLocker _(package->fCoreLock);
+		ReadSpinLocker _(package->fCoreLock);
 		entry = package->fIdleCores.Last();
 	}
 
diff --git a/src/system/kernel/scheduler/power_saving.cpp b/src/system/kernel/scheduler/power_saving.cpp
index 63ad0e3c23..75d754f178 100644
--- a/src/system/kernel/scheduler/power_saving.cpp
+++ b/src/system/kernel/scheduler/power_saving.cpp
@@ -89,12 +89,12 @@ choose_idle_core(void)
 	}
 
 	if (current == NULL) {
-		SpinLocker _(gIdlePackageLock);
+		ReadSpinLocker _(gIdlePackageLock);
 		current = gIdlePackageList->Last();
 	}
 
 	if (current != NULL) {
-		SpinLocker _(current->fCoreLock);
+		ReadSpinLocker _(current->fCoreLock);
 		return current->fIdleCores.Last();
 	}
 
diff --git a/src/system/kernel/scheduler/scheduler.cpp b/src/system/kernel/scheduler/scheduler.cpp
index 6f105f630a..ede18e6a26 100644
--- a/src/system/kernel/scheduler/scheduler.cpp
+++ b/src/system/kernel/scheduler/scheduler.cpp
@@ -66,7 +66,7 @@ int32 gCoreCount;
 
 PackageEntry* gPackageEntries;
 IdlePackageList* gIdlePackageList;
-spinlock gIdlePackageLock = B_SPINLOCK_INITIALIZER;
+rw_spinlock gIdlePackageLock = B_RW_SPINLOCK_INITIALIZER;
 int32 gPackageCount;
 
 ThreadRunQueue* gRunQueues;
@@ -132,7 +132,7 @@ PackageEntry::PackageEntry()
 	fIdleCoreCount(0),
 	fCoreCount(0)
 {
-	B_INITIALIZE_SPINLOCK(&fCoreLock);
+	B_INITIALIZE_RW_SPINLOCK(&fCoreLock);
 }
 
 
@@ -457,7 +457,7 @@ update_cpu_priority(int32 cpu, int32 priority)
 	int32 package = gCPUToPackage[cpu];
 	PackageEntry* packageEntry = &gPackageEntries[package];
 	if (maxPriority == B_IDLE_PRIORITY) {
-		SpinLocker _(packageEntry->fCoreLock);
+		WriteSpinLocker _(packageEntry->fCoreLock);
 
 		// core goes idle
 		ASSERT(packageEntry->fIdleCoreCount >= 0);
@@ -468,11 +468,11 @@ update_cpu_priority(int32 cpu, int32 priority)
 
 		if (packageEntry->fIdleCoreCount == packageEntry->fCoreCount) {
 			// package goes idle
-			SpinLocker _(gIdlePackageLock);
+			WriteSpinLocker _(gIdlePackageLock);
 			gIdlePackageList->Add(packageEntry);
 		}
 	} else if (corePriority == B_IDLE_PRIORITY) {
-		SpinLocker _(packageEntry->fCoreLock);
+		WriteSpinLocker _(packageEntry->fCoreLock);
 
 		// core wakes up
 		ASSERT(packageEntry->fIdleCoreCount > 0);
@@ -483,7 +483,7 @@ update_cpu_priority(int32 cpu, int32 priority)
 
 		if (packageEntry->fIdleCoreCount + 1 == packageEntry->fCoreCount) {
 			// package wakes up
-			SpinLocker _(gIdlePackageLock);
+			WriteSpinLocker _(gIdlePackageLock);
 			gIdlePackageList->Remove(packageEntry);
 		}
 	}
@@ -956,9 +956,6 @@ choose_next_thread(int32 thisCPU, Thread* oldThread, bool putAtBack)
 static inline void
 track_cpu_activity(Thread* oldThread, Thread* nextThread, int32 thisCore)
 {
-	bigtime_t now = system_time();
-	bigtime_t usedTime = now - oldThread->scheduler_data->quantum_start;
-
 	if (!thread_is_idle_thread(oldThread)) {
 		bigtime_t active
 			= (oldThread->kernel_time - oldThread->cpu->last_kernel_time)
@@ -976,9 +973,6 @@ track_cpu_activity(Thread* oldThread, Thread* nextThread, int32 thisCore)
 	if (!gSingleCore && !gCPU[smp_get_current_cpu()].disabled)
 		compute_cpu_load(smp_get_current_cpu());
 
-	int32 oldPriority = get_effective_priority(oldThread);
-	int32 nextPriority = get_effective_priority(nextThread);
-
 	if (!thread_is_idle_thread(nextThread)) {
 		oldThread->cpu->last_kernel_time = nextThread->kernel_time;
 		oldThread->cpu->last_user_time = nextThread->user_time;
diff --git a/src/system/kernel/scheduler/scheduler_common.h b/src/system/kernel/scheduler/scheduler_common.h
index 1fdb26f8f1..f379ba9e36 100644
--- a/src/system/kernel/scheduler/scheduler_common.h
+++ b/src/system/kernel/scheduler/scheduler_common.h
@@ -106,7 +106,7 @@ struct PackageEntry : public DoublyLinkedListLinkImpl<PackageEntry> {
 
 	int32						fPackageID;
 
-	spinlock					fCoreLock;
+	rw_spinlock					fCoreLock;
 
 	DoublyLinkedList<CoreEntry>	fIdleCores;
 	int32						fIdleCoreCount;
@@ -117,7 +117,7 @@ typedef DoublyLinkedList<PackageEntry> IdlePackageList;
 
 extern PackageEntry* gPackageEntries;
 extern IdlePackageList* gIdlePackageList;
-extern spinlock gIdlePackageLock;
+extern rw_spinlock gIdlePackageLock;
 extern int32 gPackageCount;
 
 // The run queues. Holds the threads ready to run ordered by priority.