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【环球报资讯】C# 获取电脑内存、CPU信息

来源:博客园

计数器、WMI

获取设备的内存信息,如系统可用运行内存:


(资料图片)

1     public static async Task GetMemoryAvailableAsync(FileSizeUnit fileSizeUnit = FileSizeUnit.GB) 2     { 3         return await Task.Run(() => 4         { 5             using var managementClass = new ManagementClass("Win32_PerfFormattedData_PerfOS_Memory"); 6             using var instances = managementClass.GetInstances(); 7             double available = 0; 8             foreach (var mo in instances) 9             {10                 //AvailableMBytes单位是MB11                 var size = long.Parse(mo.Properties["AvailableMBytes"].Value.ToString()) * 1024 * 1024;12                 available += size.ConvertTo(fileSizeUnit);13             }14 15             return available;16         });17     }

以上是ManagementClass方式实现,还有ManagementObjectSearcher,都是WMI检索查询。

WMI查询比较慢,上面一段耗时在200ms+。

还有一种用的较多的,PerformanceCounter性能计数器,以CPU获取为例:

1     public static async Task GetUsageByCounterAsync() 2     { 3         //CPU计数器  4         using var pcCpuUsage = new PerformanceCounter("Processor", "% Processor Time", "_Total") { MachineName = "." }; 5         // NextValue首次会返回0,所以需要加个延时下次再获取值 6         pcCpuUsage.NextValue(); 7         await Task.Delay(TimeSpan.FromMilliseconds(500)); 8         var cpuUsed = pcCpuUsage.NextValue(); 9         return cpuUsed;10     }

性能计数器,也有一定的耗时40ms以上。另外因为它实现方式,初始化后无法第一次获取到真正数值,需要间隔一段时间再去拿。所以此方案实际耗时挺高

WMI、性能计数器,昨天遇到了使用异常:

看源码,计数器是注册表PerformanceData位置损坏了,而Management是IWbemServices获取状态码ErrorCode异常。

PerformanceCounter是WMI,而WMI是基于WBEM协议实现的,所以我理解成上面的异常其实是一类问题。

官网有对此类异常有一些描述:重新生成性能计数器库值 - Windows Server | Microsoft Learn

所以基于PerformanceCounter、ManagementClass以及ManagementObjectSearcher的实现,有一定风险。

kernel32

kernel32下有个函数可以获取内存状态

1     [DllImport("kernel32.dll")]2     [return: MarshalAs(UnmanagedType.Bool)]3     static extern bool GlobalMemoryStatusEx(ref MEMORYINFO mi);

以下是获取可用运行内存的实现:

//Define the information structure of memory    [StructLayout(LayoutKind.Sequential)]    struct MEMORYINFO    {        public uint dwLength; //Current structure size        public uint dwMemoryLoad; //Current memory utilization        public ulong ullTotalPhys; //Total physical memory size        public ulong ullAvailPhys; //Available physical memory size        public ulong ullTotalPageFile; //Total Exchange File Size        public ulong ullAvailPageFile; //Total Exchange File Size        public ulong ullTotalVirtual; //Total virtual memory size        public ulong ullAvailVirtual; //Available virtual memory size        public ulong ullAvailExtendedVirtual; //Keep this value always zero    }    ///     /// Get the current memory usage    ///     ///     private static MEMORYINFO GetMemoryStatus()    {        MEMORYINFO memoryInfo = new MEMORYINFO();        memoryInfo.dwLength = (uint)System.Runtime.InteropServices.Marshal.SizeOf(memoryInfo);        GlobalMemoryStatusEx(ref memoryInfo);        return memoryInfo;    }    ///     /// 获取系统可用运行内存    ///     /// 默认单位GB    ///     public static double GetMemoryAvailable(FileSizeUnit fileSizeUnit = FileSizeUnit.GB)    {        var memoryStatus = GetMemoryStatus();        var memoryAvailable = ((long)memoryStatus.ullAvailPhys).ConvertTo(fileSizeUnit);        return memoryAvailable;    }

上述方式,获取速度超快,几乎不耗时。

通过Kernel32方式,获取CPU信息(CPU比例计算逻辑,代码略多点):

1     ///  2     /// 获取CPU占用率/使用率(单位:%) 3     ///  4     ///  5     public static async Task GetUsageByKernelAsync() 6     { 7         long idleTime1 = 0; 8         long kernelTime1 = 0; 9         long userTime1 = 0;10         if (GetSystemTimes(out var lpIdleTime, out var lpKernelTime, out var lpUserTime))11         {12             idleTime1 = lpIdleTime;13             kernelTime1 = lpKernelTime;14             userTime1 = lpUserTime;15         }16         //添加俩次获取CPU信息的间隔17         await Task.Delay(TimeSpan.FromSeconds(0.5));18         long idleTime2 = 0;19         long kernelTime2 = 0;20         long userTime2 = 0;21         if (GetSystemTimes(out var lpIdleTime2, out var lpKernelTime2, out var lpUserTime2))22         {23             idleTime2 = lpIdleTime2;24             kernelTime2 = lpKernelTime2;25             userTime2 = lpUserTime2;26         }27         //分别获取到用户时间、内核时间、空闲时间28         var userTime = userTime2 - userTime1;29         var kernelTime = kernelTime2 - kernelTime1;30         var idleTime = idleTime2 - idleTime1;31         //计算Cpu占用率。计算公式:用户时间+内核时间-空闲时间/用户时间+内核时间32         var systemTotal = kernelTime + userTime;33         var cpu = (systemTotal - idleTime) * 10000 / systemTotal;34         return cpu / 100.0;35     }36 37     /// 38     /// 获取系统CPU时间数据39     /// 40     /// 空闲时间41     /// 内核时间42     /// 用户时间43     /// 44     [DllImport("kernel32.dll", SetLastError = true)]45     static extern bool GetSystemTimes(out long lpIdleTime, out long lpKernelTime, out long lpUserTime);

另外,也有一种途径可以获取到内存信息,引用程序集Microsoft.VisualBasic,Microsoft.VisualBasic.Devices下有个ComputerInfo类

var physicalMemory = new Microsoft.VisualBasic.Devices.ComputerInfo().AvailablePhysicalMemory;

可以拿到可用内存、总内存,不过CPU信息是没有的。

ComputerInfo的内部源码,我标注了下:

所以ComputerInfo,也是基于GlobalMemoryStatusEx函数做了封装,大家可以直接用。

参考列表:

How to get system specs (processor, memory etc...) in C#? (microsoft.com)Get the CPU Usage in C# | Delft StackC#获取CPU和内存使用率 - 雨水的命运 - 博客园 (cnblogs.com)Determine CPU usage of current process (C++ and C#) | Philosophical GeekGet CPU Usage with GetSystemTimes - CodeProject

关键词: 内核时间 性能计数器 运行内存