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停機時間

停機時間 是系統上次啟動後的時間量,以 100 奈秒間隔為單位。 當系統啟動時,插斷時間計數會從零開始,並在每一個時鐘中斷時以時鐘刻度長度遞增。 時鐘刻度的實際長度取決於基礎硬體,而且在系統之間可能會有所不同。

不同于 系統時間,停機時間計數不會受限於使用者或 Windows 時間服務的調整,因此更適合用來測量短期持續時間。 需要比插斷時間計數更高的精確度的應用程式應該使用 高解析度計時器。 使用 QueryPerformanceFrequency 函式來擷取高解析度計時器和 QueryPerformanceCounter 函 式的頻率,以擷取計數器的值。

QueryInterruptTimeQueryInterruptTimePreciseQueryUnbiasedInterruptTimeQueryUnbiasedInterruptTimePrecise函式可用來擷取停機時間計數。 無偏差的停機時間表示只有系統處於工作狀態的時間才會計算,因此,系統花費在睡眠或休眠的時間不會「偏差」停機時間計數。

Windows Server 2008、Windows Vista、Windows Server 2003 和 Windows XP/2000: 從 Windows 7 和 Windows Server 2008 R2 開始,即可使用 QueryUnbiasedInterruptTime 函式。

timeBeginPeriodtimeEndPeriod函式所設定的計時器解析度會影響QueryInterruptTimeQueryUnbiasedInterruptTime函式的解析度。 不過,不建議增加計時器解析度,因為它可以降低整體系統效能,並防止處理器進入省電狀態來增加耗電量。 相反地,應用程式應該使用高解析度計時器。

注意

QueryInterruptTime、QueryInterruptTimePreciseQueryUnbiasedInterruptTime 和 QueryUnbiasedInterruptTimePrecise函式會在 Windows 的偵錯 (「核取」) 組建上產生不同的結果,因為停機時間計數和刻度計數大約會進階 49 天。 這有助於識別在系統長時間執行之前可能不會發生的 Bug。 已核取的組建可透過 Microsoft Developer Network (MSDN) 網站提供給 MSDN 訂閱者使用。

 

下列範例示範如何藉由呼叫QueryInterruptTime、QueryInterruptTimePreciseQueryUnbiasedInterruptTime 和 QueryUnbiasedInterruptTimePrecise函式來擷取停機時間計數。 當您建置呼叫這些函式的主控台應用程式時,OneCore.lib 程式庫的連結。

#include "stdafx.h"
#include <windows.h>
#include <realtimeapiset.h>

void InterruptTimeTest()
{
    ULONGLONG InterruptTime;
    ULONGLONG PreciseInterruptTime;
    ULONGLONG UnbiasedInterruptTime;
    ULONGLONG PreciseUnbiasedInterruptTime;

        // The interrupt time that QueryInterruptTime reports is based on the 
        // latest tick of the system clock timer. The system clock timer is 
        // the hardware timer that periodically generates interrupts for the 
        // system clock. The uniform period between system clock timer 
        // interrupts is referred to as a system clock tick, and is typically 
        // in the range of 0.5 milliseconds to 15.625 milliseconds, depending 
        // on the hardware platform. The interrupt time value retrieved by 
        // QueryInterruptTime is accurate within a system clock tick.

    QueryInterruptTime(&InterruptTime);
    printf("Interrupt time: %.7f seconds\n", 
            (double)InterruptTime/(double)10000000);

        // Precise interrupt time is more precise than the interrupt time that
        // QueryInterruptTime reports because the functions that report  
        // precise interrupt time read the timer hardware directly.

    QueryInterruptTimePrecise(&PreciseInterruptTime);
    printf("Precise interrupt time: %.7f seconds\n", 
            (double)PreciseInterruptTime/(double)10000000);

        // Unbiased interrupt time means that only time that the system is in 
        // the working state is counted. Therefore, the interrupt-time count 
        // is not biased by time the system spends in sleep or hibernation.

    QueryUnbiasedInterruptTime(&UnbiasedInterruptTime);
    printf("Unbiased interrupt time: %.7f seconds\n", 
            (double)UnbiasedInterruptTime/(double)10000000);

        // QueryUnbiasedInterruptTimePrecise gets an interrupt-time count
        // that is both unbiased and precise, as defined in the comments
        // included earlier in this example.

    QueryUnbiasedInterruptTimePrecise(&PreciseUnbiasedInterruptTime);
    printf("Precise unbiased interrupt time: %.7f seconds\n", 
            (double)PreciseUnbiasedInterruptTime/(double)10000000);

}

int main(void)
{
    void InterruptTimeTime();

    InterruptTimeTest();
    return(0);
}

若要擷取考慮睡眠或休眠的經過時間,請使用 GetTickCountGetTickCount64 函式,或使用系統啟動時間效能計數器。 此效能計數器可以從登錄機碼中的效能資料 擷取HKEY_PERFORMANCE_DATA。 傳回的值是 8 位元組值。 如需相關資訊,請參閱 Performance Counters

QueryInterruptTime

QueryInterruptTimePrecise

QueryUnbiasedInterruptTime

QueryUnbiasedInterruptTimePrecise

timeBeginPeriod

timeEndPeriod