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我正在使用以下代码针对已编译的正则表达式测试 CompileToAssembly 性能，但结果不合适。请让我知道我错过了什么。谢谢！！！

static readonly Regex regex = new Regex(@"(stats|pause\s?(all|\d+(\,\d+)*)|start\s?(all|\d+(\,\d+)*)|add\s?time\s?(all|\d+(\,\d+)*)(\s\d+)|c(?:hange)?\s?p(?:asskey)?|close)(.*)", RegexOptions.Compiled);
static readonly Regex reg = new Regex(@"(stats|pause\s?(all|\d+(\,\d+)*)|start\s?(all|\d+(\,\d+)*)|add\s?time\s?(all|\d+(\,\d+)*)(\s\d+)|c(?:hange)?\s?p(?:asskey)?|close)(.*)");
static readonly Regex level4 = new DuplicatedString();

    static void Main()
    {
        const string str = "add time 243,3453,43543,543,534534,54534543,345345,4354354235,345435,34543534 6873brekgnfkjerkgiengklewrij";
        const int itr = 1000000;
        CompileToAssembly();
        Match match;
        Stopwatch sw = new Stopwatch();
        sw.Start();
        for (int i = 0; i < itr; i++)
        {
             match = regex.Match(str);
        }
        sw.Stop();
        Console.WriteLine("RegexOptions.Compiled: {0}ms", sw.ElapsedMilliseconds);

        sw.Reset();
        sw.Start();
        for (int i = 0; i < itr; i++)
        {
            match = level4.Match(str);
        }
        sw.Stop();

        Console.WriteLine("CompiledToAssembly: {0}ms", sw.ElapsedMilliseconds);

        sw.Reset();
        sw.Start();
        for (int i = 0; i < itr; i++)
        {
            match = reg.Match(str);
        }
        sw.Stop();
        Console.WriteLine("Interpreted: {0}ms", sw.ElapsedMilliseconds);
        Console.ReadLine();
    }

    public static void CompileToAssembly()
    {
        RegexCompilationInfo expr;
        List<RegexCompilationInfo> compilationList = new List<RegexCompilationInfo>();

        // Define regular expression to detect duplicate words
        expr = new RegexCompilationInfo(@"(stats|pause\s?(all|\d+(\,\d+)*)|start\s?(all|\d+(\,\d+)*)|add\s?time\s?(all|\d+(\,\d+)*)(\s\d+)|c(?:hange)?\s?p(?:asskey)?|close)(.*)",
                   RegexOptions.Compiled,
                   "DuplicatedString",
                   "Utilities.RegularExpressions",
                   true);
        // Add info object to list of objects
        compilationList.Add(expr);

        // Apply AssemblyTitle attribute to the new assembly
        //
        // Define the parameter(s) of the AssemblyTitle attribute's constructor 
        Type[] parameters = { typeof(string) };
        // Define the assembly's title
        object[] paramValues = { "General-purpose library of compiled regular expressions" };
        // Get the ConstructorInfo object representing the attribute's constructor
        ConstructorInfo ctor = typeof(System.Reflection.AssemblyTitleAttribute).GetConstructor(parameters);
        // Create the CustomAttributeBuilder object array
        CustomAttributeBuilder[] attBuilder = { new CustomAttributeBuilder(ctor, paramValues) };

        // Generate assembly with compiled regular expressions
        RegexCompilationInfo[] compilationArray = new RegexCompilationInfo[compilationList.Count];
        AssemblyName assemName = new AssemblyName("RegexLib, Version=1.0.0.1001, Culture=neutral, PublicKeyToken=null");
        compilationList.CopyTo(compilationArray);
        Regex.CompileToAssembly(compilationArray, assemName, attBuilder);
    }

以下是结果：

RegexOptions.Compiled: 3908ms
CompiledToAssembly: 59349ms
Interpreted: 5653ms
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2 回答 2

6

Your code has a problem: static field initializers will run before static methods run. That means that level4 has already been assigned before Main() runs. This means that the object referred to by level4 is not an instance of the class created in CompileToAssembly().

Note that the example code for Regex.CompileToAssembly shows the compilation of the regex and its consumption in two different programs. The actual regex you're timing as "CompiledToAssembly" could therefore be a different regex that you compiled in an earlier test.

Another factor to consider: the overhead of loading an assembly into memory and jitting it to machine code might be significant enough that you need more than 1,000,000 iterations to see a benefit.

于 2012-04-09T20:35:52.240 回答
4

您正在调试器 (Visual Studio) 下运行。它将防止在加载程序集时发生 JIT 优化。尝试在没有调试器的情况下运行 (ctrl-f5)。

于 2012-04-09T20:41:50.587 回答