在花了一些时间阅读了几个看起来相当复杂的不同线程后，我想到了这个。我需要它为一个8核的机器，我想监视SQL server。对于下面的代码，我将“sqlservr”作为appName传入。

private static void RunTest(string appName)
{
    bool done = false;
    PerformanceCounter total_cpu = new PerformanceCounter("Process", "% Processor Time", "_Total");
    PerformanceCounter process_cpu = new PerformanceCounter("Process", "% Processor Time", appName);
    while (!done)
    {
        float t = total_cpu.NextValue();
        float p = process_cpu.NextValue();
        Console.WriteLine(String.Format("_Total = {0}  App = {1} {2}%\n", t, p, p / t * 100));
        System.Threading.Thread.Sleep(1000);
    }
}

它似乎正确地测量了我的8核服务器上SQL所使用的CPU百分比。

这似乎对我有用，一个等待处理器达到一定百分比的例子

var cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total");
int usage = (int) cpuCounter.NextValue();
while (usage == 0 || usage > 80)
{
     Thread.Sleep(250);
     usage = (int)cpuCounter.NextValue();
}

比要求的多一点，但我使用额外的计时器代码来跟踪和警报，如果CPU使用率在持续1分钟或更长时间内达到90%或更高。

public class Form1
{

    int totalHits = 0;

    public object getCPUCounter()
    {

        PerformanceCounter cpuCounter = new PerformanceCounter();
        cpuCounter.CategoryName = "Processor";
        cpuCounter.CounterName = "% Processor Time";
        cpuCounter.InstanceName = "_Total";

                     // will always start at 0
        dynamic firstValue = cpuCounter.NextValue();
        System.Threading.Thread.Sleep(1000);
                    // now matches task manager reading
        dynamic secondValue = cpuCounter.NextValue();

        return secondValue;

    }


    private void Timer1_Tick(Object sender, EventArgs e)
    {
        int cpuPercent = (int)getCPUCounter();
        if (cpuPercent >= 90)
        {
            totalHits = totalHits + 1;
            if (totalHits == 60)
            {
                Interaction.MsgBox("ALERT 90% usage for 1 minute");
                totalHits = 0;
            }                        
        }
        else
        {
            totalHits = 0;
        }
        Label1.Text = cpuPercent + " % CPU";
        //Label2.Text = getRAMCounter() + " RAM Free";
        Label3.Text = totalHits + " seconds over 20% usage";
    }
}

这个类每1秒自动轮询一次计数器，也是线程安全的:

public class ProcessorUsage
{
    const float sampleFrequencyMillis = 1000;

    protected object syncLock = new object();
    protected PerformanceCounter counter;
    protected float lastSample;
    protected DateTime lastSampleTime;

    /// <summary>
    /// 
    /// </summary>
    public ProcessorUsage()
    {
        this.counter = new PerformanceCounter("Processor", "% Processor Time", "_Total", true);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public float GetCurrentValue()
    {
        if ((DateTime.UtcNow - lastSampleTime).TotalMilliseconds > sampleFrequencyMillis)
        {
            lock (syncLock)
            {
                if ((DateTime.UtcNow - lastSampleTime).TotalMilliseconds > sampleFrequencyMillis)
                {
                    lastSample = counter.NextValue();
                    lastSampleTime = DateTime.UtcNow;
                }
            }
        }

        return lastSample;
    }
}

对于那些仍然无法获得与任务管理器匹配的CPU使用总数的人，您应该使用以下语句:

new PerformanceCounter("Processor Information", "% Processor Utility", "_Total");

没事的，我知道了!谢谢你的帮助!

下面是代码:

private void button1_Click(object sender, EventArgs e)
{
    selectedServer = "JS000943";
    listBox1.Items.Add(GetProcessorIdleTime(selectedServer).ToString());
}

private static int GetProcessorIdleTime(string selectedServer)
{
    try
    {
        var searcher = new
           ManagementObjectSearcher
             (@"\\"+ selectedServer +@"\root\CIMV2",
              "SELECT * FROM Win32_PerfFormattedData_PerfOS_Processor WHERE Name=\"_Total\"");

        ManagementObjectCollection collection = searcher.Get();
        ManagementObject queryObj = collection.Cast<ManagementObject>().First();

        return Convert.ToInt32(queryObj["PercentIdleTime"]);
    }
    catch (ManagementException e)
    {
        MessageBox.Show("An error occurred while querying for WMI data: " + e.Message);
    }
    return -1;
}