Monitoring CPU usage

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通过一个简单的控制组件，您可以监控移动设备的CPU使用情况。该组件包括两个定时器：一个用于周期性调用绘图函数，另一个（低优先级空闲）用于计算空闲时间。这样，您就可以大致了解其他线程的CPU使用情况。

Monitoring CPU usage

From Forum Nokia Wiki

This simple control allows you to monitor CPU usage in your mobile. To use it, just instantiate the control and set two timers: one is used to periodically invoke the plot function, and the other one (low priority idle) to count the idle time. This way, you can get an approximation on how much cpu other threads are using.

void CSystemView::ConstructL()

{

    iUpdateTimer = CPeriodic::NewL(CActive::EPriorityHigh);

    iIdleTimer = CPeriodic::NewL(CActive::EPriorityIdle);

}

 

void CSystemView::CmdStartTimers()

{

    // Reset counters

    iIdleCounter = 0;

    iCPUControl->Reset();

    DrawDeferred();

 

    const TInt KUpdateInterval = 1000000;   // 1 sec

    iUpdateTimer->Start(KUpdateInterval, KUpdateInterval, TCallBack(DoUpdateL, this));

 

    const TInt KIdleInterval = 10000;    // 0.01 sec

    iIdleTimer->Start(KIdleInterval, KIdleInterval, TCallBack(DoIdleL, this));

}

 

TInt CSystemView::DoUpdateL(TAny* aPtr)

{

    CSystemView* self = static_cast<CSystemView*>(aPtr);

 

    TInt idle = self->iIdleCounter;

    self->iIdleCounter = 0;

 

    self->iCPUControl->PlotL(idle);

 

    return 0;

}

 

TInt CSystemView::DoIdleL(TAny* aPtr)

{

    CSystemView* self = static_cast<CSystemView*>(aPtr);

    ++self->iIdleCounter;

 

    return 0;

}

#include <coecntrl.h>   // CCoeControl

 

class CCPUControl : public CCoeControl

{

public:

    void ConstructL(const TRect& aRect, const CCoeControl* aParent);

    ~CCPUControl();

 

    void Reset();

    void PlotL(TInt aIdleCounter);

 

private:

    void Draw(const TRect& aRect) const;

    void SizeChanged();

 

private:

    CArrayFix<TReal32>* iCpuLoadList;

    TInt iMaxIdleCounter;

    TReal32 iCpuLoad;

    TReal32 iTotalCpuLoad;

    TUint32 iTotalTicks;

 

    CArrayFix<TPoint>* iPointList;

    TRect iPaintRect;

 

    HBufC* iCPULoadText;

};

#include "CPUControl.h"

#include <YourApp.rsg>

 

#include <coemain.h>    // CCoeEnv

#include <eikenv.h>     // CEikonEnv

 

// Handle any possible FPU exception

void FpHandler(TExcType /*aType*/)

{}

 

void CCPUControl::ConstructL(const TRect& aRect, const CCoeControl* aParent)

{

    if (aParent == 0)

        CreateWindowL();

    else

        SetContainerWindowL(*aParent);

 

    #if defined(__S603RD__)

    User::SetExceptionHandler(FpHandler, KExceptionFpe);

    #else

    RThread().SetExceptionHandler(FpHandler, KExceptionFpe);

    #endif

 

    iCpuLoadList = new(ELeave) CArrayFixSeg<TReal32>(5);

    iPointList = new(ELeave) CArrayFixFlat<TPoint>(5);

 

    iCPULoadText = iCoeEnv->AllocReadResourceL(R_TEXT_CPU_LOAD);

 

    SetRect(aRect);

    ActivateL();

}

 

CCPUControl::~CCPUControl()

{

    delete iCPULoadText;

 

    delete iPointList;

    delete iCpuLoadList;

}

 

void CCPUControl::Reset()

{

    iCpuLoadList->Reset();

    iCpuLoad = 0;

    iTotalCpuLoad = 0;

    iTotalTicks = 0;

    iMaxIdleCounter = 0;

 

    iPointList->Reset();

}

 

void CCPUControl::Draw(const TRect& /*aRect*/) const

{

    CWindowGc& gc = SystemGc();

 

    gc.Clear(iPaintRect);

    gc.SetClippingRect(iPaintRect);

    gc.SetPenColor(KRgbRed);

    gc.DrawPolyLine(iPointList);

 

    gc.SetPenColor(KRgbBlack);

    gc.DrawRect(iPaintRect);

 

    const CFont* font = iEikonEnv->LegendFont();

    gc.UseFont(font);

 

    TBuf<64> cpuLoadText;

    cpuLoadText.Format(*iCPULoadText, static_cast<TInt>(iCpuLoad * 100), 

iTotalTicks? (iTotalCpuLoad / iTotalTicks) * 100 : 0);

 

    gc.DrawText(cpuLoadText, iPaintRect, font->HeightInPixels(), CGraphicsContext::ERight);

    gc.DiscardFont();

}

 

void CCPUControl::SizeChanged()

{

    iPaintRect = Rect();

    iPaintRect.Shrink(5, 5);

}

 

void CCPUControl::PlotL(TInt aIdleCounter)

{

    if (aIdleCounter > iMaxIdleCounter)

        iMaxIdleCounter = aIdleCounter;

 

    iCpuLoad = static_cast<TReal32> ((0.8 * (iMaxIdleCounter - aIdleCounter)) 

/ iMaxIdleCounter + 0.2 * iCpuLoad);

    // To calculate average load

    iTotalCpuLoad += iCpuLoad;    

    ++iTotalTicks;

 

    if (iCpuLoadList->Count() == iPaintRect.Width() - 2)

        iCpuLoadList->Delete(0);

    iCpuLoadList->AppendL(iCpuLoad);

 

    iPointList->Reset();

    for (TInt i = 0; i < iCpuLoadList->Count(); ++i)

    {

        TInt x = iPaintRect.iBr.iX - 1 - iCpuLoadList->Count() + i;

    	TInt y = iPaintRect.iBr.iY - 2 - 

static_cast<TInt> (iPaintRect.Height() * iCpuLoadList->At(i));

        iPointList->AppendL(TPoint(x, y));

    }

 

    DrawDeferred();

}