// Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

 // All rights reserved.

 // This component and the accompanying materials are made available

 // under the terms of the License "Eclipse Public License v1.0"

 // which accompanies this distribution, and is available

 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

 //

 // Initial Contributors:

 // Nokia Corporation - initial contribution.

 //

 // Contributors:

 //

 // Description:

 // Other possible inputs to thrashing detection:

 // - cache size and free ram

 // - pin failures

 //

 #include <kernel/kern_priv.h>

 #include "mthrash.h"

 const TInt KUpdatePeriod = 1000;   // Update every second

 DThrashMonitor TheThrashMonitor;

 DThrashMonitor::DThrashMonitor() :

 	iRunning(EFalse),

 	iUpdateTimer(NULL, this),

 	iUpdateDfc(UpdateDfcFunc, this, 0),

 	iThrashLevel(0),

 	iThresholdThrashing(200),

 	iThresholdGood(150)

 	{

 	}

 void DThrashMonitor::Start()

 	{

 	TBool alreadyRunning = __e32_atomic_swp_ord32(&iRunning, ETrue);

 	if (alreadyRunning)

 		return;

 	// reset

 	memclr(&iCount[0], sizeof(iCount));

 	iLastUpdateTime = NKern::TickCount();

 	iUpdateDfc.SetDfcQ(Kern::DfcQue0());

 	TInt r = iUpdateTimer.OneShot(KUpdatePeriod, iUpdateDfc);

 	__NK_ASSERT_ALWAYS(r == KErrNone);

 	}

 TInt DThrashMonitor::ThrashLevel()

 	{

 	return iThrashLevel;

 	}

 TInt DThrashMonitor::SetThresholds(TUint aThrashing, TUint aGood)

 	{

 	if (aThrashing < aGood || aThrashing > 255)

 		return KErrArgument;

 	iThresholdThrashing = aThrashing;

 	iThresholdGood = aGood;

 	return KErrNone;

 	}

 void DThrashMonitor::UpdateCount(TCount aCount, TInt aDelta)

 	{

 	TCountData& c = iCount[aCount];

 	NKern::FMWait(&iMutex);

 	TUint32 currentTime = NKern::TickCount();

 	c.iTotal += (TInt64)c.iCount * (currentTime - c.iLastUpdateTime);

 	c.iCount += aDelta;

 	c.iLastUpdateTime = currentTime;

 	if(!iUpdateTimer.IsPending())	

 		{

 		TInt r = iUpdateTimer.OneShot(KUpdatePeriod, iUpdateDfc);

 		__NK_ASSERT_ALWAYS(r == KErrNone);

 		}

 	NKern::FMSignal(&iMutex);

 	__NK_ASSERT_DEBUG(c.iCount >= 0);

 	}

 void DThrashMonitor::NotifyStartPaging()

 	{

 	UpdateCount(ECountThreadsPaging, 1);

 	}

 void DThrashMonitor::NotifyEndPaging()

 	{

 	UpdateCount(ECountThreadsPaging, -1);

 	}

 void DThrashMonitor::UpdateDfcFunc(TAny* aPtr)

 	{

 	DThrashMonitor* self = (DThrashMonitor*)aPtr;

 	self->RecalculateThrashLevel();

 	}

 void DThrashMonitor::RecalculateThrashLevel()

 	{

 	TInt currentTime = NKern::TickCount();

 	TInt elapsedTicks = currentTime - iLastUpdateTime;

 	NKern::FMWait(&iMutex);

 	for (TInt i = 0 ; i < EMaxCount ; ++i)

 		{

 		TCountData& c = iCount[i];

 		c.iTotal += (TInt64)c.iCount * (currentTime - c.iLastUpdateTime);

 		c.iAverage = (TInt)((256 * c.iTotal) / elapsedTicks);

 		c.iTotal = 0;

 		c.iLastUpdateTime = currentTime;

 		}

 	NKern::FMSignal(&iMutex);

 	TInt pagingActivity = Min(iCount[ECountThreadsPaging].iAverage, 255);

 	// Base thrash level entirely on the average number of threads paging

 	TInt newThrashLevel = pagingActivity;

 	TInt oldThrashLevel = iThrashLevel;

 	// Make thrash level increase slowly over time, but decrease quickly

 	if (newThrashLevel > oldThrashLevel)

 		newThrashLevel = (3 * oldThrashLevel + pagingActivity) >> 2;

 	iThrashLevel = newThrashLevel;

 	// Notify user-side if thrashing thresholds passed

 	TBool notifyChange = EFalse;

 	if (oldThrashLevel < iThresholdThrashing && newThrashLevel >= iThresholdThrashing)

 		{

 		iIsThrashing = ETrue;

 		notifyChange = ETrue;

 		}

 	else if (iIsThrashing && oldThrashLevel >= iThresholdGood && newThrashLevel < iThresholdGood)

 		{

 		iIsThrashing = EFalse;

 		notifyChange = ETrue;

 		}

 	if (notifyChange)

 		{

 		NKern::ThreadEnterCS();

 		Kern::AsyncNotifyChanges(EChangesThrashLevel);

 		NKern::ThreadLeaveCS();

 		}

 	iLastUpdateTime = currentTime;

 	if(iThrashLevel != 0)

 	    {

 	    NKern::FMWait(&iMutex);

 	    if(!iUpdateTimer.IsPending())

 	        {

             TInt r = iUpdateTimer.Again(KUpdatePeriod);

             if (r == KErrArgument)

                 {

                 r = iUpdateTimer.OneShot(KUpdatePeriod, iUpdateDfc);  

                 }

             __NK_ASSERT_ALWAYS(r == KErrNone);

 	        }

         NKern::FMSignal(&iMutex);    

 	    }

 	}