Expression.Compile 与 Lambda、直接与虚拟调用的性能
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【中文标题】Expression.Compile 与 Lambda、直接与虚拟调用的性能【英文标题】：Performance of Expression.Compile vs Lambda, direct vs virtual calls 【发布时间】：2016-06-18 18:03:34 【问题描述】：我很好奇Expression.Compile 与代码中的 lambda 表达式、直接方法使用以及直接方法调用与虚拟方法调用（伪代码）的性能如何：
var foo = new Foo();
var iFoo = (IFoo)foo;
foo.Bar();
iFoo.Bar();
(() => foo.Bar())();
(() => iFoo.Bar())();
Expression.Compile(foo, Foo.Bar)();
Expression.Compile(iFoo, IFoo.Bar)();
Expression.CompileToMethod(foo, Foo.Bar);
Expression.CompileToMethod(iFoo, IFoo.Bar);
MethodInfo.Invoke(foo, Foo.Bar);
MethodInfo.Invoke(iFoo, IFoo.Bar);
【问题讨论】：
“有多好”是什么意思？您是否在寻找执行性能？ 【参考方案1】：我没有找到任何答案，所以这里是性能测试：
using System;
using System.Diagnostics;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
namespace ExpressionTest
public interface IFoo
int Bar();
public sealed class FooImpl : IFoo
public int Bar()
return 0;
class Program
static void Main(string[] args)
var foo = new FooImpl();
var iFoo = (IFoo)foo;
Func<int> directLambda = () => foo.Bar();
Func<int> virtualLambda = () => iFoo.Bar();
var compiledDirectCall = CompileBar(foo, asInterfaceCall: false);
var compiledVirtualCall = CompileBar(foo, asInterfaceCall: true);
var compiledArgDirectCall = CompileBar<FooImpl>();
var compiledArgVirtualCall = CompileBar<IFoo>();
var barMethodInfo = typeof(FooImpl).GetMethod(nameof(FooImpl.Bar));
var iBarMethodInfo = typeof(IFoo).GetMethod(nameof(IFoo.Bar));
var compiledToModuleDirect = CompileToModule<FooImpl>();
var compiledToModuleVirtual = CompileToModule<IFoo>();
var iterationCount = 200000000;
Console.WriteLine($"Iteration count: iterationCount:N0");
var sw = Stopwatch.StartNew();
for (int i = 0; i < iterationCount; i++)
compiledVirtualCall();
var elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledDirectCall();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledArgVirtualCall(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<IFoo, int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledArgDirectCall(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<FooImpl, int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledToModuleVirtual(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<IFoo, int>)Expression.CompileToMethod(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledToModuleDirect(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<FooImpl, int>)Expression.CompileToMethod(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
virtualLambda();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual () => IFoo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
directLambda();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct () => FooImpl.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
iFoo.Bar();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual IFoo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
foo.Bar();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct Foo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
int result = (int)iBarMethodInfo.Invoke(iFoo, null);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual MethodInfo.Invoke(FooImpl, Bar): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
int result = (int)barMethodInfo.Invoke(foo, null);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct MethodInfo.Invoke(IFoo, Bar): elapsedMs ms");
static Func<int> CompileBar(IFoo foo, bool asInterfaceCall)
var fooType = asInterfaceCall ? typeof(IFoo) : foo.GetType();
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Constant(foo, fooType);
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call);
var compiledFunction = (Func<int>)lambda.Compile();
return compiledFunction;
static Func<TInput, int> CompileBar<TInput>()
var fooType = typeof(TInput);
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Parameter(fooType, "foo");
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call, instance);
var compiledFunction = (Func<TInput, int>)lambda.Compile();
return compiledFunction;
static Func<TInput, int> CompileToModule<TInput>()
var fooType = typeof(TInput);
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Parameter(fooType, "foo");
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call, instance);
var asmName = new AssemblyName(fooType.Name);
var asmBuilder = AssemblyBuilder.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.Run);
var moduleBuilder = asmBuilder.DefineDynamicModule(fooType.Name);
var typeBuilder = moduleBuilder.DefineType(fooType.Name, TypeAttributes.Public);
var methodBuilder = typeBuilder.DefineMethod(nameof(IFoo.Bar), MethodAttributes.Static, typeof(int), new[] fooType );
Expression.Lambda<Action>(lambda).CompileToMethod(methodBuilder);
var createdType = typeBuilder.CreateType();
var mi = createdType.GetMethods(BindingFlags.NonPublic | BindingFlags.Static)[1];
var func = Delegate.CreateDelegate(typeof(Func<TInput, int>), mi);
return (Func<TInput, int>)func;
在我的笔记本电脑上（发布模式，64 位，.NET 4.5.2）它产生：
Iteration count: 200,000,000
Virtual MethodInfo.Invoke(FooImpl, Bar): 61811 ms
Direct MethodInfo.Invoke(IFoo, Bar): 37078 ms
Virtual (Func<int>)Expression.Compile(): 2894 ms
Direct (Func<int>)Expression.Compile(): 2242 ms
Virtual (Func<IFoo, int>)Expression.Compile(): 2319 ms
Direct (Func<FooImpl, int>)Expression.Compile(): 2051 ms
Virtual (Func<IFoo, int>)Expression.CompileToMethod(): 996 ms
Direct (Func<FooImpl, int>)Expression.CompileToMethod(): 679 ms
Virtual () => IFoo.Bar(): 796 ms
Direct () => FooImpl.Bar(): 469 ms
Virtual IFoo.Bar(): 531 ms
Direct Foo.Bar(): 68 ms
希望这会有所帮助。
【讨论】：
但如果直接不能内联它会有所作为。 @Serge Semenov：感谢您花时间测试和发布结果。值得一提的是 CreateDelegate。我发现它与 CompileToMethod 一样快或更快，并且代码更简单：var func = (Func<T, int>)Delegate.CreateDelegate(typeof(Func<T, int>), null, methodInfo);【参考方案2】：
我们可以将一个问题分为两种情况：
.NET 如何处理方法调用本身（基础架构问题）？ 优化器如何协助方法调用？ExpressionTest.exe 在发布模式优化（默认发布设置）.NET 4.5.2：
Compiled Virtual Call: 4625 ms
Compiled Direct Call: 3361 ms
Lambda Virtual Call: 1096 ms
Lambda Direct Call: 576 ms
Virtual Call: 649 ms
Direct Call: 144 ms
我们看到“直接呼叫”比“虚拟呼叫”快 4.5 倍。但正如我们在上面看到的，这根本不是电话。 Bar 方法已内联。
ExpressionTest.exe 在发布模式没有优化 .NET 4.5.2：
Compiled Virtual Call: 5394 ms
Compiled Direct Call: 4666 ms
Lambda Virtual Call: 1800 ms
Lambda Direct Call: 1683 ms
Virtual Call: 1154 ms
Direct Call: 1112 ms
因此，“直接呼叫”比“虚拟呼叫”快 3-4%。
类似的问题： Performance of "direct" virtual call vs. interface call in C#
【讨论】：
我更感兴趣的是为什么 Expression.Compile() 给出的方法版本比 lambda "() => ... " 更慢，有没有办法获得从 Expression.Compile() 优化代码？ 我也很感兴趣，为什么编译后的调用（对 Method 和 Delegate 的调用）比从 lambda 表达式动态构建新的表达式树然后执行树要慢......我' d 还对“CompileToModule”比“CompileBar”运行多长时间以及内存使用量感兴趣。【参考方案3】：我稍微修改了@Serge Semonov 的代码并在 .NET Core 3.1 上运行它 - Expression.Compile() 的性能似乎发生了巨大变化。我还添加了使用 CSharpScript 从字符串编译 lambda 的代码。请注意，.CompileToMethod 在 .NET Core 中不可用。
Virtual (Func<int>)Expression.Compile(): 908 ms
Direct (Func<int>)Expression.Compile(): 584 ms
Virtual (Func<IFoo, int>)Expression.Compile(): 531 ms
Direct (Func<FooImpl, int>)Expression.Compile(): 426 ms
Virtual (iFooArg) => iFooArg.Bar(): 622 ms
Direct (fooArg) => fooArg.Bar(): 478 ms
Virtual () => IFoo.Bar(): 640 ms
Direct () => FooImpl.Bar(): 477 ms
Virtual IFoo.Bar(): 431 ms
Direct Foo.Bar(): 319 ms
Virtual CSharpScript.EvaluateAsync: 799 ms
Direct CSharpScript.EvaluateAsync: 748 ms
Virtual CSharpScript.EvaluateAsync + Expression.Compile(): 586 ms
Direct CSharpScript.EvaluateAsync + Expression.Compile(): 423 ms
Virtual MethodInfo.Invoke(FooImpl, Bar): 43533 ms
Direct MethodInfo.Invoke(IFoo, Bar): 29012 ms
代码：
#define NET_FW //if you run this on .NET Framework and not .NET Core or .NET (5+)
using System;
using System.Diagnostics;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
using Microsoft.CodeAnalysis.CSharp.Scripting;
using Microsoft.CodeAnalysis.Scripting;
namespace ExpressionTest
public interface IFoo
int Bar();
public sealed class FooImpl : IFoo
[MethodImpl(MethodImplOptions.NoInlining)]
public int Bar()
return 0;
class Program
static void Main(string[] args)
var foo = new FooImpl();
var iFoo = (IFoo)foo;
Func<int> directLambda = () => foo.Bar();
Func<int> virtualLambda = () => iFoo.Bar();
Func<FooImpl, int> directArgLambda = fooArg => fooArg.Bar();
Func<IFoo, int> virtualArgLambda = iFooArg => iFooArg.Bar();
var compiledDirectCall = CompileBar(foo, asInterfaceCall: false);
var compiledVirtualCall = CompileBar(foo, asInterfaceCall: true);
var compiledArgDirectCall = CompileBar<FooImpl>();
var compiledArgVirtualCall = CompileBar<IFoo>();
var barMethodInfo = typeof(FooImpl).GetMethod(nameof(FooImpl.Bar));
var iBarMethodInfo = typeof(IFoo).GetMethod(nameof(IFoo.Bar));
#if NET_FW
var compiledToModuleDirect = CompileToModule<FooImpl>();
var compiledToModuleVirtual = CompileToModule<IFoo>();
#endif
var compiledViaScriptDirect = CompileViaScript<FooImpl>();
var compiledViaScriptVirtual = CompileViaScript<IFoo>();
var compiledViaExprScriptDirect = CompileFromExprFromScript<FooImpl>();
var compiledViaExprScriptVirtual = CompileFromExprFromScript<IFoo>();
var iterationCount = 0;
int round = 0;
start:
if (round == 0)
iterationCount = 2000000;
Console.WriteLine($"Burn in");
Console.WriteLine($"Iteration count: iterationCount:N0");
goto doWork;
if (round == 1)
iterationCount = 200000000;
Console.WriteLine($"Iteration count: iterationCount:N0");
goto doWork;
return;
doWork:
var sw = Stopwatch.StartNew();
for (int i = 0; i < iterationCount; i++)
compiledVirtualCall();
var elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledDirectCall();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledArgVirtualCall(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<IFoo, int>)Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledArgDirectCall(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<FooImpl, int>)Expression.Compile(): elapsedMs ms");
#if NET_FW
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledToModuleVirtual(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (Func<IFoo, int>)Expression.CompileToMethod(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledToModuleDirect(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (Func<FooImpl, int>)Expression.CompileToMethod(): elapsedMs ms");
#endif
sw.Restart();
for (int i = 0; i < iterationCount; i++)
virtualArgLambda(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual (iFooArg) => iFooArg.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
directArgLambda(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct (fooArg) => fooArg.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
virtualLambda();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual () => IFoo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
directLambda();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct () => FooImpl.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
iFoo.Bar();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual IFoo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
foo.Bar();
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct Foo.Bar(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledViaScriptVirtual(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual CSharpScript.EvaluateAsync: elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledViaScriptDirect(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct CSharpScript.EvaluateAsync: elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledViaExprScriptVirtual(iFoo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual CSharpScript.EvaluateAsync + Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
compiledViaExprScriptDirect(foo);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct CSharpScript.EvaluateAsync + Expression.Compile(): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
int result = (int)iBarMethodInfo.Invoke(iFoo, null);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Virtual MethodInfo.Invoke(FooImpl, Bar): elapsedMs ms");
sw.Restart();
for (int i = 0; i < iterationCount; i++)
int result = (int)barMethodInfo.Invoke(foo, null);
elapsedMs = sw.ElapsedMilliseconds;
Console.WriteLine($"Direct MethodInfo.Invoke(IFoo, Bar): elapsedMs ms");
round++;
goto start;
static Func<int> CompileBar(IFoo foo, bool asInterfaceCall)
var fooType = asInterfaceCall ? typeof(IFoo) : foo.GetType();
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Constant(foo, fooType);
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call);
var compiledFunction = (Func<int>)lambda.Compile();
return compiledFunction;
static Func<TInput, int> CompileBar<TInput>()
var fooType = typeof(TInput);
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Parameter(fooType, "foo");
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call, instance);
var compiledFunction = (Func<TInput, int>)lambda.Compile();
return compiledFunction;
#if NET_FW
static Func<TInput, int> CompileToModule<TInput>()
var fooType = typeof(TInput);
var methodInfo = fooType.GetMethod(nameof(IFoo.Bar));
var instance = Expression.Parameter(fooType, "foo");
var call = Expression.Call(instance, methodInfo);
var lambda = Expression.Lambda(call, instance);
var asmName = new AssemblyName(fooType.Name);
var asmBuilder = AssemblyBuilder.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.Run);
var moduleBuilder = asmBuilder.DefineDynamicModule(fooType.Name);
var typeBuilder = moduleBuilder.DefineType(fooType.Name, TypeAttributes.Public);
var methodBuilder = typeBuilder.DefineMethod(nameof(IFoo.Bar), MethodAttributes.Static, typeof(int), new[] fooType );
Expression.Lambda<Action>(lambda).CompileToMethod(methodBuilder);
var createdType = typeBuilder.CreateType();
var mi = createdType.GetMethods(BindingFlags.NonPublic | BindingFlags.Static)[1];
var func = Delegate.CreateDelegate(typeof(Func<TInput, int>), mi);
return (Func<TInput, int>)func;
#endif
static Func<TInput, int> CompileViaScript<TInput>()
ScriptOptions scriptOptions = ScriptOptions.Default;
//Add reference to mscorlib
var mscorlib = typeof(System.Object).Assembly;
var systemCore = typeof(System.Func<>).Assembly;
var thisAssembly = typeof(IFoo).Assembly;
scriptOptions = scriptOptions.AddReferences(mscorlib, systemCore, thisAssembly);
var result = CSharpScript.EvaluateAsync<Func<TInput, int>>("it => it.Bar()", options: scriptOptions).Result;
return result;
static Func<TInput, int> CompileFromExprFromScript<TInput>()
ScriptOptions scriptOptions = ScriptOptions.Default;
//Add reference to mscorlib
var mscorlib = typeof(System.Object).Assembly;
var systemCore = typeof(System.Func<>).Assembly;
var thisAssembly = typeof(IFoo).Assembly;
scriptOptions = scriptOptions.AddReferences(mscorlib, systemCore, thisAssembly);
var result = CSharpScript.EvaluateAsync<Expression<Func<TInput, int>>>("it => it.Bar()", options: scriptOptions).Result;
var compiledFunction = result.Compile();
return compiledFunction;
如何使用 CSharpScript：https://joshvarty.com/2015/10/15/learn-roslyn-now-part-14-intro-to-the-scripting-api/ https://www.strathweb.com/2018/01/easy-way-to-create-a-c-lambda-expression-from-a-string-with-roslyn/
【讨论】：
感谢您的努力，@Artex4964。我将您的答案标记为正确的答案，因为它代表了最新和相关的数据。我喜欢你添加了CSharpScript 选项。
谢谢... 引起我注意的是 参数化编译表达式 比任何编译时生成的 lambdas 更快。我不知道这是为什么。测试设置并不完美（测试之间的时间变化高达 50 毫秒），但这一事实在尝试中是一致的。
任何对该主题感兴趣的人都应该自行对 Expression.Compile 进行基准测试，如果他们的平台不同的话。而且，也许也可以尝试：github.com/dadhi/FastExpressionCompiler【参考方案4】：
提示：在释放模式下，在“直接调用”情况下根本没有调用。 CPU 仅从 00B531BC (mov eax ...) 变为 00B531C8 (jl 00B531BC)。
for (int i = 0; i < iterationCount; i++)
00B531BA xor edx,edx
foo.Bar();
00B531BC mov eax,dword ptr [ebx+4] // actual loop begin
00B531BF cmp byte ptr [eax],al
for (int i = 0; i < iterationCount; i++)
00B531C1 inc edx
00B531C2 cmp edx,0BEBC200h // 0BEBC200h = 200000000
00B531C8 jl 00B531BC // loop begin address
【讨论】：
没错，它会内联，谢谢。这应该是一个评论想法以上是关于Expression.Compile 与 Lambda、直接与虚拟调用的性能的主要内容，如果未能解决你的问题，请参考以下文章
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