得到CPU的速度,较精确

王朝other·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

以前发布过一篇文章《粗略估计CPU的速度》可以得到CPU的速度,但是不是很准,这次发布一个比较准的程序。原理完全一样,只是用高精度计数器代替了Sleep。

#include <windows.h>

#include <stdio.h>

int __fastcall Frequence_MHz()

{

LARGE_INTEGER ulFreq, ulTicks, ulValue, ulResult;

__int64 ulEAX_EDX, ulStartCounter;

DWORD PriorityClass, Priority;

PriorityClass = GetPriorityClass(GetCurrentProcess());

Priority = GetThreadPriority(GetCurrentThread());

SetPriorityClass(GetCurrentProcess(), REALTIME_PRIORITY_CLASS);

SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);

// it is number of ticks per seconds

QueryPerformanceFrequency(&ulFreq);

// current valueofthe performance counter

QueryPerformanceCounter(&ulTicks);

// calculate one second interval

ulValue.QuadPart = ulTicks.QuadPart + ulFreq.QuadPart;

// read time stamp counter

// this asm instruction load the highorder 32 bit of the register into EDX

// and the lower order 32 bits into EAX

_asm {

rdtsc

mov DWORD PTR ulEAX_EDX, EAX

mov DWORD PTR (ulEAX_EDX + 4), EDX

}

// start no of ticks

ulStartCounter = ulEAX_EDX;

// loop for 1 second

do {

QueryPerformanceCounter(&ulTicks);

} while (ulTicks.QuadPart <= ulValue.QuadPart);

// get the actual no of ticks

_asm {

rdtsc

mov DWORD PTR ulEAX_EDX, EAX

mov DWORD PTR (ulEAX_EDX + 4), EDX

}

// calculate result

ulResult.QuadPart = ulEAX_EDX - ulStartCounter;

SetThreadPriority(GetCurrentThread(), Priority);

SetPriorityClass(GetCurrentProcess(), PriorityClass);

return (int)ulResult.QuadPart / 1000000;

}

int main()

{

printf("CPU speed = %d MHz\n",Frequence_MHz());

}

原作者:NowCan

来 源:http://nowcan.yeah.net

 
 
 
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