如何實時獲取系統每個進程占用的CPU

　　本文的目的是為了和大家討論一個問題，同時給出一個根據進程ID，來返回該進程實時占用的CPU使用率的函數。希望大家在用這個函數的時候別忘記我的問題。

　　目前計算進程CPU占用率的方法主要有兩種，一種是根據時間來計算，另一種根據注冊表計算，我使用的是前者。前者方法原理：在一個特定時間段內計算特定進程的總時間和所有進程的總時間，它們的比值就是那個特定進程的確CPU占有率。

　　我寫了一個函數(改寫)，以進程的ID作為參數，進程CPU占用率作為返回值，實時計算特定進程的CPU占用，測試正確。整個程序如下：

　　結構定義：

　　

typedef struct _THREAD_INFO
{
LARGE_INTEGER CreateTime;
DWORD dwUnknown1;
DWORD dwStartAddress;
DWORD StartEIP;
DWORD dwOwnerPID;
DWORD dwThreadId;
DWORD dwCurrentPriority;
DWORD dwBasePriority;
DWORD dwContextSwitches;
DWORD Unknown;
DWORD WaitReason;
}THREADINFO, *PTHREADINFO;
typedef struct _UNICODE_STRING
{
 USHORT Length;
 USHORT MaxLength;
 PWSTR Buffer;
} UNICODE_STRING;
typedef struct _PROCESS_INFO
{
DWORD dwOffset;
DWORD dwThreadsCount;
DWORD dwUnused1[6];
LARGE_INTEGER CreateTime;
LARGE_INTEGER UserTime;
LARGE_INTEGER KernelTime;
UNICODE_STRING ProcessName;
DWORD dwBasePriority;
DWORD dwProcessID;
DWORD dwParentProcessId;
DWORD dwHandleCount;
DWORD dwUnused3[2];
DWORD dwVirtualBytesPeak;
DWORD dwVirtualBytes;
ULONG dwPageFaults;
DWORD dwWorkingSetPeak;
DWORD dwWorkingSet;
DWORD dwQuotaPeakPagedPoolUsage;
DWORD dwQuotaPagedPoolUsage;
DWORD dwQuotaPeakNonPagedPoolUsage;
DWORD dwQuotaNonPagedPoolUsage;
DWORD dwPageFileUsage;
DWORD dwPageFileUsagePeak;
DWORD dCommitCharge;
THREADINFO ThreadSysInfo[1];
} PROCESSINFO, *PPROCESSINFO;

　　函數定義：

　　

int Button2Click(int id);//參數是進程ID
函數實體：
int Button2Click(int id)
{
int cpuusage;
PVOID pProcInfo = NULL;
DWORD dwInfoSize = 0x20000;
PPROCESSINFO pProcessInfo;
DWORD dwWorkingSet;
long ( __stdcall *NtQuerySystemInformation )( DWORD, PVOID, DWORD, DWORD );

static __int64 LastTotalProcessCPUUsage = 0;
static __int64 LastCurrentProcessCPUUsage = 0;
int CurrentDelta;
int TotalDelta;
__int64 TotalProcessCPUUsage = 0;
__int64 CurrentProcessCPUUsage = 0;
/////////////////////////////////
pProcInfo = (PVOID)(new byte[dwInfoSize]);
NtQuerySystemInformation = (long(__stdcall*)(DWORD,PVOID,DWORD,DWORD))
GetProcAddress( GetModuleHandle( "ntdll.dll" ),"NtQuerySystemInformation" );
NtQuerySystemInformation(5,pProcInfo,dwInfoSize,0);
pProcessInfo = (PPROCESSINFO)pProcInfo;
do
{
TotalProcessCPUUsage += (__int64)pProcessInfo->KernelTime.QuadPart + (__int64)pProcessInfo->UserTime.QuadPart;
if(pProcessInfo->dwProcessID == id)
{
dwWorkingSet = pProcessInfo->dwWorkingSet;
CurrentProcessCPUUsage += (__int64)pProcessInfo->KernelTime.QuadPart + (__int64)pProcessInfo->UserTime.QuadPart;
}
/////////
if(pProcessInfo->dwOffset == 0)
{
break;
}
pProcessInfo = (PPROCESSINFO)((byte*)pProcessInfo + pProcessInfo->dwOffset);
}
while(true);
TotalDelta = TotalProcessCPUUsage - LastTotalProcessCPUUsage;
CurrentDelta = CurrentProcessCPUUsage - LastCurrentProcessCPUUsage;
if(TotalDelta != 0)
cpuusage = 100 * CurrentDelta / TotalDelta;
//this->Caption = "CPU = " + IntToStr(100 * CurrentDelta / TotalDelta) +
//"Memory = "+ IntToStr(dwWorkingSet / 1024) " K";
LastTotalProcessCPUUsage = TotalProcessCPUUsage;
LastCurrentProcessCPUUsage = CurrentProcessCPUUsage;
delete[] pProcInfo;
return cpuusage;
}

　　控制台調用：

　　

int main(void)
{
 while(true)
 {
　
        int s = Button2Click(0);//在此把進程ID作為參數傳入
　
        printf("%d\n",s);
　
        Sleep(1000);
 }
 return 0;
}

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　　以上代碼運行非常正常

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