diff --git a/stepmania/src/arch/ArchHooks/ArchHooks_darwin.cpp b/stepmania/src/arch/ArchHooks/ArchHooks_darwin.cpp
index 163709d4c6..51422dac7f 100644
--- a/stepmania/src/arch/ArchHooks/ArchHooks_darwin.cpp
+++ b/stepmania/src/arch/ArchHooks/ArchHooks_darwin.cpp
@@ -1,15 +1,26 @@
 #include "global.h"
 #include "ArchHooks_darwin.h"
 #include "RageLog.h"
+#include "RageThreads.h"
+#include "RageTimer.h"
 #include "RageUtil.h"
 #include "archutils/Darwin/Crash.h"
 #include "archutils/Unix/CrashHandler.h"
 #include "archutils/Unix/SignalHandler.h"
 #include "ProductInfo.h"
 #include <Carbon/Carbon.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <mach/thread_act.h>
 #include <mach/mach.h>
 #include <mach/host_info.h>
 #include <mach/mach_time.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#if 0 // Time critical stuff
+static thread_time_constraint_policy g_oldttcpolicy;
+static float g_fStartedTimeCritAt;
+#endif
 
 static bool IsFatalSignal( int signal )
 {
@@ -55,6 +66,8 @@ ArchHooks_darwin::ArchHooks_darwin()
 	SignalHandler::OnClose( DoCrashSignalHandler );
 #endif
 	
+	//TimeCritMutex = new RageMutex("TimeCritMutex");
+	
 	// CF*Copy* functions' return values need to be released, CF*Get* functions' do not.
 	CFStringRef key = CFSTR( "ApplicationBundlePath" );
 	
@@ -103,6 +116,11 @@ ArchHooks_darwin::ArchHooks_darwin()
 	CFRelease( path );
 }
 
+ArchHooks_darwin::~ArchHooks_darwin()
+{
+	//delete TimeCritMutex;
+}
+
 void ArchHooks_darwin::DumpDebugInfo()
 {
 	RString systemVersion;
@@ -207,6 +225,53 @@ RString ArchHooks::GetPreferredLanguage()
 	return ret.ToUpper();
 }
 
+void ArchHooks_darwin::EnterTimeCriticalSection()
+{
+#if 0
+	TimeCritMutex->Lock();
+
+	int mib[] = { CTL_HW, HW_BUS_FREQ };
+	int miblen = ARRAYSIZE( mib );
+	int bus_speed;
+	size_t len = sizeof (bus_speed);
+	if( sysctl( mib, miblen, &bus_speed, &len, NULL, 0 ) == -1 )
+	{
+		LOG->Warn( "sysctl(HW_BUS_FREQ): %s", strerror(errno) );
+		return;
+	}
+
+	mach_msg_type_number_t cnt = THREAD_TIME_CONSTRAINT_POLICY_COUNT;
+	boolean_t bDefaults = false;
+	thread_policy_get( mach_thread_self(), THREAD_TIME_CONSTRAINT_POLICY, (int*)&g_oldttcpolicy, &cnt, &bDefaults );
+
+	/* We want to monopolize the CPU for a very short period of time.  This means that the
+	 * period doesn't really matter, and we don't want to be preempted.  Set the period
+	 * very high (~1 second), so that if we ever lose the CPU when we shouldn't, we can
+	 * detect it and log it in ExitTimeCriticalSection(). */
+	thread_time_constraint_policy ttcpolicy;
+	ttcpolicy.period = bus_speed;
+	ttcpolicy.computation = ttcpolicy.constraint = bus_speed/60;
+	ttcpolicy.preemptible = 0;
+	thread_policy_set( mach_thread_self(), THREAD_TIME_CONSTRAINT_POLICY,
+		(int*)&ttcpolicy, THREAD_TIME_CONSTRAINT_POLICY_COUNT );
+
+	g_fStartedTimeCritAt = RageTimer::GetTimeSinceStart();
+#endif
+}
+
+void ArchHooks_darwin::ExitTimeCriticalSection()
+{
+#if 0
+	thread_policy_set( mach_thread_self(), THREAD_TIME_CONSTRAINT_POLICY,
+		(int*) &g_oldttcpolicy, THREAD_TIME_CONSTRAINT_POLICY_COUNT );
+	TimeCritMutex->Unlock();
+
+	float fTimeCritLen = RageTimer::GetTimeSinceStart() - g_fStartedTimeCritAt;
+	if( fTimeCritLen > 0.1f )
+		LOG->Warn( "Time-critical section lasted for %f", fTimeCritLen );
+#endif
+}
+
 int64_t ArchHooks::GetMicrosecondsSinceStart( bool bAccurate )
 {
 	static uint64_t iStartTime = mach_absolute_time();
diff --git a/stepmania/src/arch/ArchHooks/ArchHooks_darwin.h b/stepmania/src/arch/ArchHooks/ArchHooks_darwin.h
index e07fa88216..ba9ba21aac 100644
--- a/stepmania/src/arch/ArchHooks/ArchHooks_darwin.h
+++ b/stepmania/src/arch/ArchHooks/ArchHooks_darwin.h
@@ -8,8 +8,14 @@ class ArchHooks_darwin : public ArchHooks
 {
 public:
 	ArchHooks_darwin();
+	~ArchHooks_darwin();
 	void DumpDebugInfo();
 	RString GetPreferredLanguage();
+	void EnterTimeCriticalSection();
+	void ExitTimeCriticalSection();
+	
+protected:
+	//RageMutex *TimeCritMutex;
 };
 
 #ifdef ARCH_HOOKS
@@ -20,7 +26,7 @@ public:
 #endif /* ARCH_HOOKS_DARWIN_H */
 
 /*
- * (c) 2003-2006 Steve Checkoway
+ * (c) 2003-2005 Steve Checkoway
  * All rights reserved.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a