c# - 为什么空白线程要占用 30% 的 CPU？

Question

我编写了一个 C# 控制台应用程序。

启动后，它启动了 2 个新线程，它们根本没有做任何繁重的事情，为什么这种情况会消耗 30% 的 CPU？

这是我的代码:

class Program
{
    static DateTime LastPlayerRegistration;
    static List<Player> Players;
    static List<string> CommandsList = new List<string>
    {
        "GetPlayersNumber", "GetLastRegistration", "GetTimeElapsed", "NewPlayer"
    };
    static void Main(string[] args)
    {
        if (!File.Exists("Players.json")) File.Create("Players.json");
        Players = JsonConvert.DeserializeObject<List<Player>>(File.ReadAllText("Players.json")) ?? new List<Player>();
        new Thread(PlayerInput).Start();
        new Thread(GeneralRoutines).Start();
    }

    static void PlayerInput()
    {
        while (true)
        {
            string command = Console.ReadLine();
            string[] commandParameters = command.Split(' ');
            switch (commandParameters[0].ToLower())
            {
                case "getplayersnumber":
                    Console.WriteLine("There are " + Players.Count + " players registered!");
                    break;
                case "getlastregistration":
                    Console.WriteLine("Last registration happened at " + LastPlayerRegistration);
                    break;
                case "gettimeelapsed":
                    Console.WriteLine((DateTime.Now - LastPlayerRegistration) + " time elapsed from last registration");
                    break;
                case "newplayer":
                    if (commandParameters.Count() > 1 && !string.IsNullOrEmpty(commandParameters[1]))
                    {
                        DateTime now = DateTime.Now;
                        TimeSpan elapsed = (now - LastPlayerRegistration);
                        LastPlayerRegistration = now;
                        Players.Add(new Player(commandParameters[1], elapsed));
                        Console.WriteLine("Player " + commandParameters[1] + " created!");
                    }
                    else
                    {
                        Console.WriteLine("Player Name is missing!");
                    }
                    break;
                default:
                    Console.WriteLine("'" + command + "' command is not defined.");
                    break;
            }
        }
    }

    static void GeneralRoutines()
    {
        DateTime lastPlayersListSave = DateTime.Now;
        while (true)
        {
            if ((int)(DateTime.Now - lastPlayersListSave).Seconds >= 30)
            {
                File.WriteAllText("Players.json", JsonConvert.SerializeObject(Players));
                Console.WriteLine("Players list saved!");
                lastPlayersListSave = DateTime.Now;
            }
        }
    }
}

class Player
{
    public Guid ID { get; set; }
    public string Name { get; set; }
    public TimeSpan Elapsed { get; set; }

    [JsonConstructor]
    public Player(Guid id, string name, TimeSpan elapsed)
    {
        this.ID = id;
        this.Name = name;
        this.Elapsed = elapsed;
    }
    public Player(string name, TimeSpan elapsed)
    {
        this.ID = Guid.NewGuid();
        this.Name = name;
        this.Elapsed = elapsed;
    }
}

Answer 1

it starts 2 new threads which aren't doing anything heavy at all

嗯，我很确定它说的是 while (true) 这将继续运行该代码，直到所有 CPU 能力都被耗尽，并且在那个紧密的循环中它会不断分配(并最终释放)内存。没有什么可以阻止该代码尽可能快地运行，从而及时分配大量内存。

你应该稍微延迟执行。例如，您可以使用 Thread.Sleep(1000) 在“无操作”的情况下延迟执行一秒钟。