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  • 如何获得CPU使用率(转)

    #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");
    }

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  • 原文地址:https://www.cnblogs.com/mazhenyu/p/1413325.html
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