正在使用Lazy T对性能不好吗? [英] Is using Lazy<T> bad for performance?

问题描述

最近，我在singelton类中遇到了一些问题，该类懒惰地初始化字典，在该字典中，第二个线程将在实际填充它之前尝试使用它.因此，我通过

Recently I was having some issues with a singelton class that was lazy initializing a dictionary where a second thread would try to use it before it had actually been populated. So I implemented the variable initialization through the Lazy<T> class.

这是我的代码:

private static Dictionary<string, string> GroupDefaults
{
    get { return mGroupDefaults.Value; }
}
private static Lazy<Dictionary<string, string>> mGroupDefaults =
    new Lazy<Dictionary<string,string>>(delegate
    {
        Dictionary<string, string> defaults = new Dictionary<string, string>();
        foreach (KeyValuePair<string, UnitGroup> groupDef in Groups)
            defaults.Add(groupDef.Key, groupDef.Value.First().Key);
        return defaults;
    });

这解决了问题，现在我考虑将其作为我的常规做法，在我进行延迟初始化的任何地方使用 Lazy< T> 类，以避免任何可能的线程问题.因此，基本上我想知道这是否是好的/常见的做法?还是会对性能或某些东西产生不利影响?

This fixed the problem and now I am considering making this a regular practice of mine to use the Lazy<T> class anywhere I do lazy initialization to avoid any possible threading issues. So basically I would like to know if this is good/common practice? Or will it be detremental to performance or something?

推荐答案

在不知道您具有哪种类型的性能约束的情况下很难说，但是根据我的经验，一次性初始化很少会成为瓶颈(因为从定义上讲，只会发生一次.)编写 Lazy< T> 是为了向您提供此确切服务，所以我建议使用它.

It's pretty hard to say without knowing what type of performance constraints you have, but in my experience, one-time initialization is rarely a bottleneck (since by definition it only occurs once.) Lazy<T> was written to provide you with this exact service, so I would recommend using it.

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