如何获得CPU使用率

2019-11-17 05:33:37

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来源：转载

供稿：网友

　　NT/2000方法：

#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
     &nb

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