c# - 执行前预编译 C# 方法

Question

我这样测量代码速度:

var sw = new Stopwatch();
sw.Start();
DoSomething();
sw.Stop();
AddLog("Method speed is (ms): "+sw.ElapsedMilliseconds);

但是第一次调用 DoSomething() 很慢，因为代码正在编译。解决方法是像这样测量第二次调用的速度:

var sw = new Stopwatch();
DoSomething();
sw.Start();
DoSomething();
sw.Stop();
AddLog("Method speed is (ms): "+sw.ElapsedMilliseconds);

有没有办法在不先调用的情况下预编译 DoSomethig()？

Answer 1

The documentation does not unequivocally state so, but according to this article (among others) you can use the RuntimeHelpers.PrepareMethod to precompile a method.

为了详细说明我的评论(上述)，这里有一个代码示例:

static void WarmUp()
{
    var handle = typeof (Program).GetMethod("DoSomething").MethodHandle;
    RuntimeHelpers.PrepareMethod(handle);
}

更新

这是一个更通用(虽然有点脆弱)的解决方案，它也将考虑实例成员:

public static class MethodWarmerUper
{
    public static void WarmUp(string methodName)
    {
        var handle = FindMethodWithName(methodName).MethodHandle;
        RuntimeHelpers.PrepareMethod(handle);
    }

    private static MethodInfo FindMethodWithName(string methodName)
    {
        return 
            Assembly.GetExecutingAssembly()
                    .GetTypes()
                    .SelectMany(type => type.GetMethods(MethodBindingFlags))
                    .FirstOrDefault(method => method.Name == methodName);
    }

    private const BindingFlags MethodBindingFlags =
        BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic |
        BindingFlags.Instance | BindingFlags.Static;
}