有没有办法通过 .NET / C＃找出CPU内核的数量？
PS这是一个直接的代码问题，而不是“我应该使用多线程吗？”题！ ： - ）
答案 0 :(得分：442)
您可以获得与处理器相关的几种不同信息：
这些都可以是不同的;对于具有2个支持双核超线程处理器的计算机，有2个物理处理器，4个核心和8个逻辑处理器。
Environment类可以使用逻辑处理器的数量，但其他信息只能通过WMI获得（您可能需要安装一些hotfixes or service packs才能使用{{3}}系统）：
确保将项目中的引用添加到System.Management.dll
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"]);
}
<强>芯：
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"]);
}
从Windows中排除的处理器：
您还可以在 setupapi.dll 中使用Windows API调用来发现已从Windows中排除的处理器（例如，通过启动设置），并且无法使用上述方法检测到。下面的代码给出了存在的逻辑处理器总数（我无法弄清楚如何区分物理处理器和逻辑处理器），包括那些已从Windows中排除的处理器：
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 - 1;
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,
}
答案 1 :(得分：187)
Environment.ProcessorCount
答案 2 :(得分：28)
WMI查询速度很慢，因此请尝试仅选择所需的成员，而不是使用Select *。
以下查询需要3.4s：
foreach (var item in new System.Management.ManagementObjectSearcher("Select * from Win32_Processor").Get())
虽然这个需要0.122秒：
foreach (var item in new System.Management.ManagementObjectSearcher("Select NumberOfCores from Win32_Processor").Get())
答案 3 :(得分：19)
Environment.ProcessorCount应该为您提供本地计算机上的核心数。
答案 4 :(得分：4)
您也可以使用Kernel32.dll上的 PInvoke 获取
以下代码或多或少来自位于here的System.Web源的SystemInfo.cs：
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct SYSTEM_INFO
{
public ushort wProcessorArchitecture;
public ushort wReserved;
public uint dwPageSize;
public IntPtr lpMinimumApplicationAddress;
public IntPtr lpMaximumApplicationAddress;
public IntPtr dwActiveProcessorMask;
public uint dwNumberOfProcessors;
public uint dwProcessorType;
public uint dwAllocationGranularity;
public ushort wProcessorLevel;
public ushort wProcessorRevision;
}
internal static class SystemInfo
{
static int _trueNumberOfProcessors;
internal static readonly IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);
[DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
internal static extern void GetSystemInfo(out SYSTEM_INFO si);
[DllImport("kernel32.dll")]
internal static extern int GetProcessAffinityMask(IntPtr handle, out IntPtr processAffinityMask, out IntPtr systemAffinityMask);
internal static int GetNumProcessCPUs()
{
if (SystemInfo._trueNumberOfProcessors == 0)
{
SYSTEM_INFO si;
GetSystemInfo(out si);
if ((int) si.dwNumberOfProcessors == 1)
{
SystemInfo._trueNumberOfProcessors = 1;
}
else
{
IntPtr processAffinityMask;
IntPtr systemAffinityMask;
if (GetProcessAffinityMask(INVALID_HANDLE_VALUE, out processAffinityMask, out systemAffinityMask) == 0)
{
SystemInfo._trueNumberOfProcessors = 1;
}
else
{
int num1 = 0;
if (IntPtr.Size == 4)
{
uint num2 = (uint) (int) processAffinityMask;
while ((int) num2 != 0)
{
if (((int) num2 & 1) == 1)
++num1;
num2 >>= 1;
}
}
else
{
ulong num2 = (ulong) (long) processAffinityMask;
while ((long) num2 != 0L)
{
if (((long) num2 & 1L) == 1L)
++num1;
num2 >>= 1;
}
}
SystemInfo._trueNumberOfProcessors = num1;
}
}
}
return SystemInfo._trueNumberOfProcessors;
}
}
答案 5 :(得分：4)
最简单的方式= Environment.ProcessorCount
例如Environment.ProcessorCount Property
using System;
class Sample
{
public static void Main()
{
Console.WriteLine("The number of processors " +
"on this computer is {0}.",
Environment.ProcessorCount);
}
}
答案 6 :(得分：1)
以下程序打印Windows机器的逻辑和物理内核。
#define STRICT
#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <omp.h>
template<typename T>
T *AdvanceBytes(T *p, SIZE_T cb)
{
return reinterpret_cast<T*>(reinterpret_cast<BYTE *>(p) + cb);
}
class EnumLogicalProcessorInformation
{
public:
EnumLogicalProcessorInformation(LOGICAL_PROCESSOR_RELATIONSHIP Relationship)
: m_pinfoBase(nullptr), m_pinfoCurrent(nullptr), m_cbRemaining(0)
{
DWORD cb = 0;
if (GetLogicalProcessorInformationEx(Relationship,
nullptr, &cb)) return;
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) return;
m_pinfoBase =
reinterpret_cast<SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *>
(LocalAlloc(LMEM_FIXED, cb));
if (!m_pinfoBase) return;
if (!GetLogicalProcessorInformationEx(Relationship,
m_pinfoBase, &cb)) return;
m_pinfoCurrent = m_pinfoBase;
m_cbRemaining = cb;
}
~EnumLogicalProcessorInformation() { LocalFree(m_pinfoBase); }
void MoveNext()
{
if (m_pinfoCurrent) {
m_cbRemaining -= m_pinfoCurrent->Size;
if (m_cbRemaining) {
m_pinfoCurrent = AdvanceBytes(m_pinfoCurrent,
m_pinfoCurrent->Size);
} else {
m_pinfoCurrent = nullptr;
}
}
}
SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *Current()
{ return m_pinfoCurrent; }
private:
SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *m_pinfoBase;
SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *m_pinfoCurrent;
DWORD m_cbRemaining;
};
int __cdecl main(int argc, char **argv)
{
int numLogicalCore = 0;
int numPhysicalCore = 0;
for (EnumLogicalProcessorInformation enumInfo(RelationProcessorCore);
auto pinfo = enumInfo.Current(); enumInfo.MoveNext())
{
int numThreadPerCore = (pinfo->Processor.Flags == LTP_PC_SMT) ? 2 : 1;
// std::cout << "thread per core: "<< numThreadPerCore << std::endl;
numLogicalCore += numThreadPerCore;
numPhysicalCore += 1;
}
printf ("Number of physical core = %d , Number of Logical core = %d \n", numPhysicalCore, numLogicalCore );
char c = getchar(); /* just to wait on to see the results in the command prompt */
return 0;
}
/*
I tested with Intel Xeon four cores with hyper threading and here is the result
Number of physical core = 4 , Number of Logical core = 8
*/
答案 7 :(得分：1)
一种选择是从注册表中读取数据。 MSDN关于主题的文章：http://msdn.microsoft.com/en-us/library/microsoft.win32.registry.localmachine(v=vs.71).aspx）
处理器，我相信可以在这里，HKEY_LOCAL_MACHINE \ HARDWARE \ DESCRIPTION \ System \ CentralProcessor
private void determineNumberOfProcessCores()
{
RegistryKey rk = Registry.LocalMachine;
String[] subKeys = rk.OpenSubKey("HARDWARE").OpenSubKey("DESCRIPTION").OpenSubKey("System").OpenSubKey("CentralProcessor").GetSubKeyNames();
textBox1.Text = "Total number of cores:" + subKeys.Length.ToString();
}
我有理由相信大多数系统都会有注册表项。
虽然我会把我的0.02美元扔进去。
答案 8 :(得分：0)
我一直在寻找相同的东西，但我不想安装任何nuget或servicepack，所以我找到了这个解决方案，它非常简单直接， 使用this讨论，我认为运行WMIC命令并获得该值非常容易，这里是C＃代码。您只需要使用System.Management命名空间（并为进程连接更多标准命名空间等）。
string fileName = Path.Combine(Environment.SystemDirectory, "wbem", "wmic.exe");
string arguments = @"cpu get NumberOfCores";
Process process = new Process
{
StartInfo =
{
FileName = fileName,
Arguments = arguments,
UseShellExecute = false,
CreateNoWindow = true,
RedirectStandardOutput = true,
RedirectStandardError = true
}
};
process.Start();
StreamReader output = process.StandardOutput;
Console.WriteLine(output.ReadToEnd());
process.WaitForExit();
int exitCode = process.ExitCode;
process.Close();
答案 9 :(得分：0)
这里已经有很多答案，但是有些答案很不正确。
.NET Environment.ProcessorCount将返回不正确的值，并且如果系统WMI配置不正确，则可能会严重失败。
如果您想要一种可靠的方法来计数内核，唯一的方法是Win32 API。
这是一个C ++代码段：
#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，因此是移植的版本：
[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();
答案 10 :(得分：0)
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;
}
}
}