（大家讨论一下）如何通过编程取得CPU的利用率？

Question

如题，该使用哪个函数呢？

Answer 1

seePerformance Monitor - Get System Counter Values (CPU, Memory, etc.) 
http://codeguru.earthweb.com/system/perfmon.shtmlor see
http://msdn.microsoft.com/library/en-us/perfmon/base/using_performance_monitoring.asp?frame=true

Answer 2

占用率// cpusagent.cpp (Windows NT/2000)//// Getting the CPU usage in percent on Windows NT/2000//// (c)2000 Ashot Oganesyan K, SmartLine, Inc// mailto:[email protected], http://www.protect-me.com, http://www.codepile.com#include <windows.h>#include <conio.h>#include <stdio.h>#define SystemBasicInformation       0#define SystemPerformanceInformation 2#define SystemTimeInformation        3#define Li2Double(x) ((double)((x).HighPart) * 4.294967296E9 + (double)((x).LowPart))typedef struct{    DWORD   dwUnknown1;    ULONG   uKeMaximumIncrement;    ULONG   uPageSize;    ULONG   uMmNumberOfPhysicalPages;    ULONG   uMmLowestPhysicalPage;    ULONG   uMmHighestPhysicalPage;    ULONG   uAllocationGranularity;    PVOID   pLowestUserAddress;    PVOID   pMmHighestUserAddress;    ULONG   uKeActiveProcessors;    BYTE    bKeNumberProcessors;    BYTE    bUnknown2;    WORD    wUnknown3;} SYSTEM_BASIC_INFORMATION;typedef struct{    LARGE_INTEGER   liIdleTime;    DWORD           dwSpare[76];} SYSTEM_PERFORMANCE_INFORMATION;typedef struct{    LARGE_INTEGER liKeBootTime;    LARGE_INTEGER liKeSystemTime;    LARGE_INTEGER liExpTimeZoneBias;    ULONG         uCurrentTimeZoneId;    DWORD         dwReserved;} SYSTEM_TIME_INFORMATION;// ntdll!NtQuerySystemInformation (NT specific!)//// The function copies the system information of the// specified type into a buffer//// NTSYSAPI// NTSTATUS// NTAPI// NtQuerySystemInformation(//    IN UINT SystemInformationClass,    // information type//    OUT PVOID SystemInformation,       // pointer to buffer//    IN ULONG SystemInformationLength,  // buffer size in bytes//    OUT PULONG ReturnLength OPTIONAL   // pointer to a 32-bit//                                       // variable that receives//                                       // the number of bytes//                                       // written to the buffer // );typedef LONG (WINAPI *PROCNTQSI)(UINT,PVOID,ULONG,PULONG);PROCNTQSI NtQuerySystemInformation;void main(void){    SYSTEM_PERFORMANCE_INFORMATION SysPerfInfo;    SYSTEM_TIME_INFORMATION        SysTimeInfo;    SYSTEM_BASIC_INFORMATION       SysBaseInfo;    double                         dbIdleTime;    double                         dbSystemTime;    LONG                           status;    LARGE_INTEGER                  liOldIdleTime = {0,0};    LARGE_INTEGER                  liOldSystemTime = {0,0};    NtQuerySystemInformation = (PROCNTQSI)GetProcAddress(                                          GetModuleHandle("ntdll"),                                         "NtQuerySystemInformation"                                         );    if (!NtQuerySystemInformation)        return;    // get number of processors in the system    status = NtQuerySystemInformation(SystemBasicInformation,&SysBaseInfo,sizeof(SysBaseInfo),NULL);    if (status != NO_ERROR)        return;     printf("\nCPU Usage (press any key to exit):    ");    while(!_kbhit())    {        // get new system time     status = NtQuerySystemInformation(SystemTimeInformation,&SysTimeInfo,sizeof(SysTimeInfo),0);        if (status!=NO_ERROR)            return;        // get new CPU's idle time        status = NtQuerySystemInformation(SystemPerformanceInformation,&SysPerfInfo,sizeof(SysPerfInfo),NULL);        if (status != NO_ERROR)            return;        // if it's a first call - skip it       if (liOldIdleTime.QuadPart != 0)       {            // CurrentValue = NewValue - OldValue            dbIdleTime = Li2Double(SysPerfInfo.liIdleTime) - Li2Double(liOldIdleTime);            dbSystemTime = Li2Double(SysTimeInfo.liKeSystemTime) - Li2Double(liOldSystemTime);            // CurrentCpuIdle = IdleTime / SystemTime            dbIdleTime = dbIdleTime / dbSystemTime;            // CurrentCpuUsage% = 100 - (CurrentCpuIdle * 100) / NumberOfProcessors            dbIdleTime = 100.0 - dbIdleTime * 100.0 / (double)SysBaseInfo.bKeNumberProcessors + 0.5;            printf("\b\b\b\b%3d%%",(UINT)dbIdleTime);       }        // store new CPU's idle and system time        liOldIdleTime = SysPerfInfo.liIdleTime;        liOldSystemTime = SysTimeInfo.liKeSystemTime;         // wait one second        Sleep(1000);    }    printf("\n");}