使所有进程并行

本文关键字：并行 进程 | 更新日期: 2023-09-27 17:54:59

我正在尝试使用c#的TPL并行获取所有进程的CPU%。我的代码是:

        private IDictionary<Process, int> _usage = new Dictionary<Process, int>();
        public ProcessCpuUsageGetter()
        {            
            Process[] processes = Process.GetProcesses();
            int processCount = processes.Count();
            Task[] tasks = new Task[processCount];
            int counter = 0;
            for (int i = 0; i < processCount; i++)
            {
                tasks[i] = Task.Factory.StartNew(() => DoWork(processes[i]));
            }
            Task.WaitAll(tasks);
        }
        private void DoWork(object o)
        {
            Process process = (Process)o;
            PerformanceCounter pc = new PerformanceCounter("Process", "% Processor Time", process.ProcessName, true);
            pc.NextValue();
            Thread.Sleep(1000);
            int cpuPercent = (int)pc.NextValue() / Environment.ProcessorCount;
            _usage.Add(process, cpuPercent);
        }

但是它失败了与An item with the same key has already been added.任何想法我做错了什么?

使所有进程并行

问题是当传递给启动任务的表达式时，局部变量i的闭包。这导致即使i被for修改，DoWork(processes[i])也会使用i的电流值。

创建一个局部变量:

for (int i = 0; i < processCount; i++)
{
     int localI = i;
     tasks[i] = Task.Factory.StartNew(() => DoWork(processes[localI]));
}
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