QueryPerformanceCounter 이용한 StopWatch 클래스

#pragma once

class CAStopWatch
{
private:
    int     m_Initialized;
    BOOL    m_BeginFlag;
    __int64 m_Frequency;
    __int64 m_BeginTime;
    __int64 m_EndTime;

    __int64 m_i64Elapsed;
    double  m_dblElapsed;

public:
    CAStopWatch(void)
    {
        // Get CPU Frequency
        m_Initialized = QueryPerformanceFrequency((LARGE_INTEGER *)&m_Frequency);

        m_BeginFlag   = FALSE;
    }

    virtual ~CAStopWatch(void)
    {
    }

    BOOL Begin()
    {
        if( !m_Initialized )
        {
            return 0;
        }
    
        // Get Begin Counter
        m_BeginFlag = QueryPerformanceCounter( (LARGE_INTEGER *)&m_BeginTime );

        return m_BeginFlag;
    }

    double End()
    {
        if( !m_Initialized || !m_BeginFlag )
        {
            return 0.0;
        }

        // Get End Counter
        QueryPerformanceCounter( (LARGE_INTEGER *)&m_EndTime );

        // calculate elapse count
        m_i64Elapsed = m_EndTime - m_BeginTime;

        // Convert count to second
        m_dblElapsed = (double)m_i64Elapsed / (double)m_Frequency;

        return m_dblElapsed;
    }

    BOOL Available()
    {
        return m_Initialized; 
    }

    __int64 GetFreq()
    { 
        return m_Frequency; 
    }

    double GetElapsedTime()
    {
        return m_dblElapsed;
    }

    double GetElapsedSecond()
    {
        return m_dblElapsed;
    }

    double GetElapsedMillisecond()
    {
        return m_dblElapsed * 1000;
    }

    double GetElapsedMicroSecond()
    {
        return m_dblElapsed * 1000000;
    }
};

// 사용 예
CAStopWatch watch;

watch.Begin();
    :
    :
watch.End();

double sec = watch.GetElapsedSecond();
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Original Post : http://neodreamer-dev.tistory.com/391

QueryPerformanceCounter 함수를 이용한 시간 측정

#include 
#include 

__int64 ctr1 = 0, ctr2 = 0, freq = 0;
int acc = 0, i = 0;

// Start timing the code.
if (QueryPerformanceCounter((LARGE_INTEGER *)&ctr1)!= 0)
{
    // Code segment is being timed.
    for (i=0; i<100; i++) acc++;

    // Finish timing the code.
    QueryPerformanceCounter((LARGE_INTEGER *)&ctr2);

    Console::WriteLine("Start Value: {0}",ctr1.ToString());
    Console::WriteLine("End Value: {0}",ctr2.ToString());
    
    QueryPerformanceFrequency((LARGE_INTEGER *)&freq);
    
    Console::WriteLine("QueryPerformanceCounter minimum resolution: 1/{0} Seconds.",freq.ToString());
    Console::WriteLine("100 Increment time: {0} seconds.",((ctr2 - ctr1) * 1.0 / freq).ToString());
}
else
{
    DWORD dwError = GetLastError();
    Console::WriteLine("Error value = {0}",dwError.ToString());
}

// Make the console window wait.
Console::WriteLine();
Console::Write("Press ENTER to finish.");
Console::Read();

return 0;

////////////////////////////////////////////////////////////////
// Result
Start Value: 192244814693193
End Value: 192244814694677
QueryPerformanceCounter minimum resolution: 1/1263460000 Seconds.
100 Increment time: 1.17455241954633E-06 seconds.

 

QueryPerformanceCounter 를 활용한 시간 측정 코드 이다. CPU 의 동작속도를 이용하여 시간을 측정하는 방법으로 GetTickCount 보다 정확한 시간을 측정할 수 있다.

출처 : MSDN<

Original Post : http://neodreamer-dev.tistory.com/372