环境。ProcessorCount应该提供本地机器上的核数。

WMI查询很慢，所以尽量只选择所需的成员，而不是使用Select *。

查询时间为3.4s:

foreach (var item in new System.Management.ManagementObjectSearcher("Select * from Win32_Processor").Get())

而这个需要0.122秒:

foreach (var item in new System.Management.ManagementObjectSearcher("Select NumberOfCores from Win32_Processor").Get())

关于处理器，你可以得到几个不同的信息:

物理处理器数量 核数 逻辑处理器数。

这些都是不同的;在具有2个支持超线程的双核处理器的机器中，有2个物理处理器、4个核心和8个逻辑处理器。

逻辑处理器的数量可以通过Environment类获得，但其他信息只能通过WMI获得(并且您可能必须安装一些修补程序或服务包才能在某些系统上获得它):

确保在项目中向System.Management.dll添加引用 在。net Core中，这是一个NuGet包(仅适用于Windows)。

物理处理器:

foreach (var item in new System.Management.ManagementObjectSearcher("Select * from Win32_ComputerSystem").Get())
{
    Console.WriteLine("Number Of Physical Processors: {0} ", item["NumberOfProcessors"]);
}

颜色:

int coreCount = 0;
foreach (var item in new System.Management.ManagementObjectSearcher("Select * from Win32_Processor").Get())
{
    coreCount += int.Parse(item["NumberOfCores"].ToString());
}
Console.WriteLine("Number Of Cores: {0}", coreCount);

逻辑处理器:

Console.WriteLine("Number Of Logical Processors: {0}", Environment.ProcessorCount);

OR

foreach (var item in new System.Management.ManagementObjectSearcher("Select * from Win32_ComputerSystem").Get())
{
    Console.WriteLine("Number Of Logical Processors: {0}", item["NumberOfLogicalProcessors"]);
}

Windows不包含的处理器:

你也可以在setupapi.dll中使用Windows API调用来发现被Windows排除的处理器(例如通过引导设置)，并且使用上述方法无法检测到这些处理器。下面的代码给出了现有逻辑处理器的总数(我还不知道如何区分物理处理器和逻辑处理器)，包括那些被Windows排除在外的处理器:

static void Main(string[] args)
{
    int deviceCount = 0;
    IntPtr deviceList = IntPtr.Zero;
    // GUID for processor classid
    Guid processorGuid = new Guid("{50127dc3-0f36-415e-a6cc-4cb3be910b65}");

    try
    {
        // get a list of all processor devices
        deviceList = SetupDiGetClassDevs(ref processorGuid, "ACPI", IntPtr.Zero, (int)DIGCF.PRESENT);
        // attempt to process each item in the list
        for (int deviceNumber = 0; ; deviceNumber++)
        {
            SP_DEVINFO_DATA deviceInfo = new SP_DEVINFO_DATA();
            deviceInfo.cbSize = Marshal.SizeOf(deviceInfo);

            // attempt to read the device info from the list, if this fails, we're at the end of the list
            if (!SetupDiEnumDeviceInfo(deviceList, deviceNumber, ref deviceInfo))
            {
                deviceCount = deviceNumber;
                break;
            }
        }
    }
    finally
    {
        if (deviceList != IntPtr.Zero) { SetupDiDestroyDeviceInfoList(deviceList); }
    }
    Console.WriteLine("Number of cores: {0}", deviceCount);
}

[DllImport("setupapi.dll", SetLastError = true)]
private static extern IntPtr SetupDiGetClassDevs(ref Guid ClassGuid,
    [MarshalAs(UnmanagedType.LPStr)]String enumerator,
    IntPtr hwndParent,
    Int32 Flags);

[DllImport("setupapi.dll", SetLastError = true)]
private static extern Int32 SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);

[DllImport("setupapi.dll", SetLastError = true)]
private static extern bool SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet,
    Int32 MemberIndex,
    ref SP_DEVINFO_DATA DeviceInterfaceData);

[StructLayout(LayoutKind.Sequential)]
private struct SP_DEVINFO_DATA
{
    public int cbSize;
    public Guid ClassGuid;
    public uint DevInst;
    public IntPtr Reserved;
}

private enum DIGCF
{
    DEFAULT = 0x1,
    PRESENT = 0x2,
    ALLCLASSES = 0x4,
    PROFILE = 0x8,
    DEVICEINTERFACE = 0x10,
}

环境。ProcessorCount应该提供本地机器上的核数。

这里已经有很多答案了，但有些得到了很高的赞，有些是不正确的。

. net环境。ProcessorCount将返回不正确的值，如果您的系统WMI配置不正确，可能会严重失败。

如果你想要一个可靠的方法来计算内核，唯一的方法是Win32 API。

下面是一个c++代码片段:

#include <Windows.h>
#include <vector>

int num_physical_cores()
{
    static int num_cores = []
    {
        DWORD bytes = 0;
        GetLogicalProcessorInformation(nullptr, &bytes);
        std::vector<SYSTEM_LOGICAL_PROCESSOR_INFORMATION> coreInfo(bytes / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION));
        GetLogicalProcessorInformation(coreInfo.data(), &bytes);

        int cores = 0;
        for (auto& info : coreInfo)
        {
            if (info.Relationship == RelationProcessorCore)
                ++cores;
        }
        return cores > 0 ? cores : 1;
    }();
    return num_cores;
}

由于这是一个。net c#问题，下面是移植版本:

[StructLayout(LayoutKind.Sequential)]
struct CACHE_DESCRIPTOR
{
    public byte Level;
    public byte Associativity;
    public ushort LineSize;
    public uint Size;
    public uint Type;
}

[StructLayout(LayoutKind.Explicit)]
struct SYSTEM_LOGICAL_PROCESSOR_INFORMATION_UNION
{
    [FieldOffset(0)] public byte ProcessorCore;
    [FieldOffset(0)] public uint NumaNode;
    [FieldOffset(0)] public CACHE_DESCRIPTOR Cache;
    [FieldOffset(0)] private UInt64 Reserved1;
    [FieldOffset(8)] private UInt64 Reserved2;
}

public enum LOGICAL_PROCESSOR_RELATIONSHIP
{
    RelationProcessorCore,
    RelationNumaNode,
    RelationCache,
    RelationProcessorPackage,
    RelationGroup,
    RelationAll = 0xffff
}

struct SYSTEM_LOGICAL_PROCESSOR_INFORMATION
{
    public UIntPtr ProcessorMask;
    public LOGICAL_PROCESSOR_RELATIONSHIP Relationship;
    public SYSTEM_LOGICAL_PROCESSOR_INFORMATION_UNION ProcessorInformation;
}

[DllImport("kernel32.dll")]
static extern unsafe bool GetLogicalProcessorInformation(SYSTEM_LOGICAL_PROCESSOR_INFORMATION* buffer, out int bufferSize);

static unsafe int GetProcessorCoreCount()
{
    GetLogicalProcessorInformation(null, out int bufferSize);
    int numEntries = bufferSize / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
    var coreInfo = new SYSTEM_LOGICAL_PROCESSOR_INFORMATION[numEntries];

    fixed (SYSTEM_LOGICAL_PROCESSOR_INFORMATION* pCoreInfo = coreInfo)
    {
        GetLogicalProcessorInformation(pCoreInfo, out bufferSize);
        int cores = 0;
        for (int i = 0; i < numEntries; ++i)
        {
            ref SYSTEM_LOGICAL_PROCESSOR_INFORMATION info = ref pCoreInfo[i];
            if (info.Relationship == LOGICAL_PROCESSOR_RELATIONSHIP.RelationProcessorCore)
                ++cores;
        }
        return cores > 0 ? cores : 1;
    }
}

public static readonly int NumPhysicalCores = GetProcessorCoreCount();

你可以使用这个类:

public static class CpuCores
{
    private static int cores = 0;
    
    public static int Number
    { 
        get
        {
            if (cores > 0) return cores;

            RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SYSTEM\CurrentControlSet\Control\Class\" +
                "{50127dc3-0f36-415e-a6cc-4cb3be910b65}");
            if (key == null)
            {
                cores = Environment.ProcessorCount;
                return cores;
            }
            string[] subkeys = key.GetSubKeyNames();
            key.Close();
            cores = 0;
            if (subkeys != null && subkeys.Length > 0) foreach (string s in subkeys)
            {
                if (s.Length != 4) continue;
                int n;
                if (int.TryParse(s, out n) && ++n > cores) cores = n;
            }
            if (cores <= 0) cores = Environment.ProcessorCount;
            return cores;
        } 
    }
}