測試1秒鐘休眠所耗費的時間

 //Timer1.cpp 使用了RDTSC指令的Timer類//KTimer類的定義可以參見《Windows圖形編程》P15

//編譯行：CL Timer1.cpp /link USER32.lib

#include <stdio.h>

#include "KTimer.h"

main()

{

unsigned t;

KTimer timer;

timer.Start();

Sleep(1000);

t = timer.Stop();

printf("Lasting Time: %dn",t);

}



//Timer2.cpp 使用了timeGetTime函數

//需包含<mmsys.h>，但由於Windows頭文件錯綜複雜的關係

//簡單包含<windows.h>比較偷懶：）

//編譯行：CL timer2.cpp /link winmm.lib

#include <windows.h>

#include <stdio.h>



main()

{

DWORD t1, t2;

t1 = timeGetTime();

Sleep(1000);

t2 = timeGetTime();

printf("Begin Time: %un", t1);

printf("End Time: %un", t2);

printf("Lasting Time: %un",(t2-t1));

}



//Timer3.cpp 使用了QueryPerformanceCounter函數

//編譯行：CL timer3.cpp /link KERNEl32.lib

#include <windows.h>

#include <stdio.h>



main()

{

LARGE_INTEGER t1, t2, tc;

QueryPerformanceFrequency(&tc);

printf("Frequency: %un", tc.QuadPart);

QueryPerformanceCounter(&t1);

Sleep(1000);

QueryPerformanceCounter(&t2);

printf("Begin Time: %un", t1.QuadPart);

printf("End Time: %un", t2.QuadPart);

printf("Lasting Time: %un",( t2.QuadPart- t1.QuadPart));

}



////////////////////////////////////////////////

//以上三個示例程序都是測試1秒鐘休眠所耗費的時間

file://測/試環境：Celeron 800MHz / 256M SDRAM

// Windows 2000 Professional SP2

// Microsoft Visual C++ 6.0 SP5

////////////////////////////////////////////////



以下是Timer1的運行結果，使用的是高精度的RDTSC指令

Lasting Time: 804586872



以下是Timer2的運行結果，使用的是最粗糙的timeGetTime API

Begin Time: 20254254

End Time: 20255255

Lasting Time: 1001



以下是Timer3的運行結果，使用的是QueryPerformanceCount API

Frequency: 3579545

Begin Time: 3804729124

End Time: 3808298836

Lasting Time: 3569712