编写一个程序，使CPU的使用率稳定在50%

Question

请问如何做到？

Answer 1

不同的CPU的速度也是不一样的
所以要根据运行情况调整

Answer 2

在工作线程中完成耗时的任务。用代码取得当前的CPU使用率，如果过高, 则Sleep.

Answer 3

写了一个双核下应该也可以吧
#include <windows.h>
#include <stdio.h>
#define RATE 0.50
#define ERROR_VALUE 0.001
#define SAMPLE_GRANULARITY 20000000
#define FILETIME_TO_LARGEINTEGER(li, ft) \
((li)->HighPart = (ft).dwHighDateTime, (li)->LowPart = (ft).dwLowDateTime)typedef struct _cpu_usage_t
{
double rate;
double lastrate;
LARGE_INTEGER start;
LARGE_INTEGER used;
LARGE_INTEGER usage;
LARGE_INTEGER total;
UINT counter;
}cpu_usage_t;typedef struct _worker_t
{
cpu_usage_t usage;
HANDLE      hd;
DWORD       mask;
}worker_t;BOOL get_cpu_usage(cpu_usage_t *pret)
{ FILETIME ftStart, ftDummy, ftKernel, ftUser, ftCurrent;
LARGE_INTEGER liKernel, liUser, liCurrent;
SYSTEMTIME stCurrentTime; if (pret->start.QuadPart == 0)
{
GetProcessTimes(GetCurrentProcess(), &ftStart, &ftDummy, &ftDummy, &ftDummy);
FILETIME_TO_LARGEINTEGER(&pret->start, ftStart);
pret->start.QuadPart = 0;
} GetSystemTime(&stCurrentTime);
SystemTimeToFileTime(&stCurrentTime, &ftCurrent);
FILETIME_TO_LARGEINTEGER(&liCurrent, ftCurrent);
pret->total.QuadPart = liCurrent.QuadPart - pret->start.QuadPart; GetProcessTimes(GetCurrentProcess(), &ftDummy, &ftDummy, &ftKernel, &ftUser);
FILETIME_TO_LARGEINTEGER(&liKernel, ftKernel);
FILETIME_TO_LARGEINTEGER(&liUser, ftUser);
pret->usage.QuadPart = liKernel.QuadPart + liUser.QuadPart - pret->used.QuadPart; pret->rate = (double)pret->usage.QuadPart / (double)pret->total.QuadPart; if (pret->total.QuadPart >= SAMPLE_GRANULARITY)
{
pret->start.QuadPart = liCurrent.QuadPart;
pret->used.QuadPart = liKernel.QuadPart + liUser.QuadPart;
pret->counter ++; 
} return TRUE;
}void use_cpu()
{
return;
}DWORD WINAPI worker(LPVOID lpPara)
{ worker_t* pworker;
double prevrate = 0.0;
UINT precounter = 0; pworker = (worker_t*)lpPara; SetThreadAffinityMask(GetCurrentThread(), pworker->mask); memset(&pworker->usage, 0, sizeof(pworker->usage));
precounter = pworker->usage.counter; while (1)
{
get_cpu_usage(&pworker->usage); if (precounter != pworker->usage.counter)
{
printf("ThreadAffinityMask:%x : %2.3f\n", pworker->mask, pworker->usage.rate);
precounter = pworker->usage.counter;
} if (pworker->usage.rate >= RATE)
{
Sleep(1);
}
else if (pworker->usage.rate < RATE)
{
use_cpu();
} }
}static worker_t _wokers[32];int _tmain(int argc, _TCHAR* argv[])
{
DWORD dwPAM, dwSAM, dwTemp1, dwTemp2, dwTemp3;
HANDLE hProc;
UINT i = 0; hProc = GetCurrentProcess();
GetProcessAffinityMask(hProc, &dwPAM, &dwSAM); dwTemp1 = dwSAM; while (dwTemp1 != 0)
{
dwTemp2 = dwTemp1 - 1;
dwTemp2 &= dwTemp1;
dwTemp3 = dwTemp2;
dwTemp2 = dwTemp2 ^ dwTemp1;
dwTemp1 = dwTemp3; if (dwTemp2 != 0)
{
_wokers[i].mask = dwTemp2;
_wokers[i].hd = CreateThread(NULL, 0, worker, (LPVOID)&_wokers[i], 0, NULL);
i++;
}
} Sleep(100000); return 0;
}

Answer 4

认真学习一下，不过这个程序在我的机器上运行 CPU的占有率为30%左右。（PS:CPU是HT的）

Answer 5

认真学习一下，不过这个程序在我的机器上运行   CPU的占有率为30%左右。（PS:CPU是HT的）
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在单核上是50%
没有考虑清楚怎么在多核上保证50%

Answer 6

把代码中的
GetProcessTimes(GetCurrentProcess(), &ftStart, &ftDummy, &ftDummy, &ftDummy);
替换成
GetThreadTimes(GetCurrentThread(), &ftStart, &ftDummy, &ftDummy, &ftDummy);