// 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;

	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;

	}