编译的Linq表达式树速度

using System; using System.Diagnostics; using System.IO; using System.Linq; using System.Linq.Expressions; using System.Reflection; using System.Text; namespace ExpressionSpeedTest { class Program { static void Main(string[] args) { InitExpression(); InitDelegateNative(); var inst = new TestClass { StringProp = "abcdefabcdef" }; byte[] buff1, buff2; using (var ms1 = new MemoryStream()) { SaveString(ms1, inst); buff1 = ms1.ToArray(); } using (var ms2 = new MemoryStream()) { DynamicMethod(ms2, inst); buff2 = ms2.ToArray(); } Console.WriteLine($"Native string: {string.Join("", buff1.Select(b => Encoding.Default.GetString(new[] { b })))}"); Console.WriteLine($"Expressions string: {string.Join("", buff2.Select(b => Encoding.Default.GetString(new[] { b })))}"); GC.Collect(GC.MaxGeneration); GC.WaitForPendingFinalizers(); GC.Collect(GC.MaxGeneration); TestNative(); GC.Collect(GC.MaxGeneration); GC.WaitForPendingFinalizers(); GC.Collect(GC.MaxGeneration); TestDelegateNative(); GC.Collect(GC.MaxGeneration); GC.WaitForPendingFinalizers(); GC.Collect(GC.MaxGeneration); TestExpressions(); GC.Collect(GC.MaxGeneration); GC.WaitForPendingFinalizers(); GC.Collect(GC.MaxGeneration); Console.ReadLine(); } private static void TestDelegateNative() { var inst = new TestClass { StringProp = "abcdefabcdef" }; using (var ms = new MemoryStream()) { var sw = new Stopwatch(); sw.Start(); for (var idx = 0; idx < loopLength; idx++) { SaveString(ms, inst); } sw.Stop(); Console.WriteLine($"Native Dlgt test: {sw.Elapsed}, {sw.ElapsedTicks} ticks"); } } private static void InitDelegateNative() { NativeDelegate = SaveString; } private static void InitExpression() { var intGetBytes = typeof(BitConverter).GetMethods(BindingFlags.Static | BindingFlags.Public) .Single(x => x.Name == nameof(BitConverter.GetBytes) && x.GetParameters()[0].ParameterType == typeof(int)); var stringGetBytes = typeof(Encoding).GetMethods(BindingFlags.Instance | BindingFlags.Public) .Single(x => x.Name == nameof(Encoding.GetBytes) && x.GetParameters().Length == 1 && x.GetParameters()[0].ParameterType == typeof(string)); var unicodeProp = typeof(Encoding).GetProperty(nameof(Encoding.Unicode), BindingFlags.Static | BindingFlags.Public); var streamWrite = typeof(Stream).GetMethod(nameof(Stream.Write)); var streamPar = Expression.Parameter(typeof(Stream), "stream"); var instPar = Expression.Parameter(typeof(TestClass), "inst"); var intBuffVar = Expression.Variable(typeof(byte[]), "intBuff"); var strBuffVar = Expression.Variable(typeof(byte[]), "strBuff"); var expressionBody = Expression.Block( new[] { intBuffVar, strBuffVar }, Expression.Assign(intBuffVar, Expression.Call(null, intGetBytes, Expression.Property( Expression.Property( instPar, nameof(TestClass.StringProp)), nameof(string.Length)))), Expression.Assign(strBuffVar, Expression.Call(Expression.Property(null, unicodeProp), stringGetBytes, Expression.Property( instPar, nameof(TestClass.StringProp) ))), Expression.Call(streamPar, streamWrite, intBuffVar, Expression.Constant(0), Expression.Property(intBuffVar, nameof(Array.Length))), Expression.Call(streamPar, streamWrite, strBuffVar, Expression.Constant(0), Expression.Property(strBuffVar, nameof(Array.Length))) ); DynamicMethod = Expression.Lambda<Action<Stream, TestClass>>(expressionBody, streamPar, instPar).Compile(); } private const int loopLength = 10000000; private static Action<Stream, TestClass> DynamicMethod; private static Action<Stream, TestClass> NativeDelegate; private static void TestExpressions() { var inst = new TestClass { StringProp = "abcdefabcdef" }; using (var ms = new MemoryStream()) { var sw = new Stopwatch(); sw.Start(); for (var idx = 0; idx < loopLength; idx++) { DynamicMethod(ms, inst); } sw.Stop(); Console.WriteLine($"Expressions test: {sw.Elapsed}, {sw.ElapsedTicks} ticks"); } } private static void TestNative() { var inst = new TestClass { StringProp = "abcdefabcdef" }; using (var ms = new MemoryStream()) { var sw = new Stopwatch(); sw.Start(); for (var idx = 0; idx < loopLength; idx++) { SaveString(ms, inst); } sw.Stop(); Console.WriteLine($"Native test: {sw.Elapsed}, {sw.ElapsedTicks} ticks"); } } public static void SaveString(Stream stream, TestClass instance) { var intBuff = BitConverter.GetBytes(instance.StringProp.Length); var strBuff = Encoding.Unicode.GetBytes(instance.StringProp); stream.Write(intBuff, 0, intBuff.Length); stream.Write(strBuff, 0, strBuff.Length); } } class TestClass { public string StringProp { get; set; } } } 

	英特尔（R）酷睿（TM）i7-3770 CPU @ 3.40GHz

	基本速度：3.90 GHz
	插座数：1
	核心数：4
	逻辑处理器：8
	虚拟化：已启用
	 L1快取：256 KB
	 L2快取：1.0 MB
	三级缓存：8.0 MB

	利用率8％
	速度4.05 GHz
	正常运行时间5：00：43：01
	流程239
	线程4092
	把手168774

	 32.0 GB DDR3

	速度：1600 MHz
	使用的插槽：4个（共4个）
	外形尺寸：DIMM
	硬件保留：42.5 MB

	可用20.7 GB
	缓存20.1 GB
	已承诺13.4 / 36.7 GB
	分页池855 MB
	非页面缓冲池442 MB
	使用中（压缩）11.2 GB（48.6 MB）

 .Lambda＃Lambda1 <System.Action`2 [System.IO.Stream，ExpressionSpeedTest.TestClass]>（
     System.IO.Stream $流，
     ExpressionSpeedTest.TestClass $ inst）{
     。块（
         System.Byte [] $ intBuff，
         System.Byte [] $ strBuff）{
         $ intBuff =。调用System.BitConverter.GetBytes（（$ inst.StringProp）.Length）;
         $ strBuff = .Call（System.Text.Encoding.Unicode）.GetBytes（$ inst.StringProp）;
        调用$ stream.Write（
             $ intBuff，
             0
             $ intBuff.Length）;
        调用$ stream.Write（
             $ strBuff，
             0
             $ strBuff.Length）
     }
 }