C# 并发容器之ConcurrentDictionary与普通Dictionary带锁的性能对比

最新推荐文章于 2025-06-22 13:02:48 发布

conquerwave

最新推荐文章于 2025-06-22 13:02:48 发布

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本文对比了C#中的并发容器ConcurrentDictionary与普通Dictionary在多线程环境下使用锁进行并发操作的性能差异。结果显示，ConcurrentDictionary在并发性能上具有显著优势，保证了高并发场景下的稳定性和效率。

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结果已经写在注释中

static void Main(string[] args)
{
    var concurrentDictionary = new ConcurrentDictionary<int, string>();
    var dictionary = new Dictionary<int, string>();

    var sw = new Stopwatch();
    sw.Start();

    for (int i = 0; i < 1000000; i++)
    {
        lock (dictionary)
        {
            dictionary[i] = Item;
        }
    }

    sw.Stop();
    Console.WriteLine("wrinting to dictionary with a lock: {0}", sw.Elapsed);
    //wrinting to dictionary with a lock: 00:00:00.0633939
    sw.Restart();
    for (int i = 0; i < 1000000; i++)
    {
        concurrentDictionary[i] = Item;
    }
    sw.Stop();
    Console.WriteLine("wrinting to a concurrent dictionary: {0}", sw.Elapsed);
    //wrinting to a concurrent dictionary: 00:00:00.2889851
    //对于写入操作并发词典要比普通带锁词典要慢
    sw.Restart();
    for (int i = 0; i < 1000000; i++)
    {
        lock (dictionary)
        {
            CurrentItem = dictionary[i];
        }
    }
    sw.Stop();
    Console.WriteLine("reading from dictionary with a lock: {0}", sw.Elapsed);
    //reading from dictionary with a lock: 00:00:00.0286066
    sw.Restart();
    for (int i = 0; i < 1000000; i++)
    {
        CurrentItem = concurrentDictionary[i];
    }
    sw.Stop();
    Console.WriteLine("reading from a concurrent dictionary: {0}", sw.Elapsed);
    //reading from a concurrent dictionary: 00:00:00.0196372
    //对于读取操作并发词典要比普通带锁词典要快
    //concurrentDictionary采用细粒度锁定[fine-grained locking]
    //普通带锁dictionary采用粗粒度锁定[coarse-grained locking]
    //在多核多线程的情况下concurrentDictionary将有更好的性能表现
    sw.Restart();

    Console.ReadKey();
}

const string Item = "Dictionary item";
public static string CurrentItem;