MapsterMapper · DocSvartz · May 17, 2026 · May 12, 2026 · May 12, 2026 · May 15, 2026
diff --git a/README.md b/README.md
@@ -141,21 +141,23 @@ public static class StudentMapper {
 
 ### Performance & Memory efficient
 
-Mapster was designed to be efficient on both speed and memory. You could gain a 4x performance improvement whilst using only 1/3 of memory.
-And you could gain up to 12x faster performance with:
+Mapster was designed to be efficient on both speed and memory. The repository includes a benchmark project in [`src/Benchmark`](src/Benchmark) that compares the local Mapster build, its compiler variants, and other modern mapping libraries like AutoMapper, Mapperly, and Facet.
 
 - [Roslyn Compiler](https://mapstermapper.github.io/Mapster/articles/packages/ExpressionDebugging.html)
 - [FEC](https://mapstermapper.github.io/Mapster/articles/packages/FastExpressionCompiler.html)
 - Code generation
-
-|                    Method |      Mean |    StdDev |     Error |      Gen 0 | Gen 1 | Gen 2 | Allocated |
-|-------------------------- |----------:|----------:|----------:|-----------:|------:|------:|----------:|
-|           'Mapster 6.0.0' | 108.59 ms |  1.198 ms |  1.811 ms | 31000.0000 |     - |     - | 124.36 MB |
-|  'Mapster 6.0.0 (Roslyn)' |  38.45 ms |  0.494 ms |  0.830 ms | 31142.8571 |     - |     - | 124.36 MB |
-|     'Mapster 6.0.0 (FEC)' |  37.03 ms |  0.281 ms |  0.472 ms | 29642.8571 |     - |     - | 118.26 MB |
-| 'Mapster 6.0.0 (Codegen)' |  34.16 ms |  0.209 ms |  0.316 ms | 31133.3333 |     - |     - | 124.36 MB |
-|     'ExpressMapper 1.9.1' | 205.78 ms |  5.357 ms |  8.098 ms | 59000.0000 |     - |     - | 236.51 MB |
-|       'AutoMapper 10.0.0' | 420.97 ms | 23.266 ms | 35.174 ms | 87000.0000 |     - |     - | 350.95 MB |
+- Facet
+- Mapperly
+
+| Method | MapOperations | Mean | StdDev | Error | Ratio | Gen0 | Gen1 | Allocated | Alloc Ratio |
+| -------- | -------------- | -----: | -------: | ------: | ------: | -----: | -----: | ----------: | ----------: |
+| `Mapster 10.0.7` | 1000000 | 412,534 us | 2,704 us | 4,543 us | 1.00 | 77000 | - | 1243.59 MB | 1.00 |
+| `Mapster 10.0.7 (Roslyn)` | 1000000 | 397,028 us | 5,174 us | 8,695 us | 0.96 | 75000 | - | 1205.44 MB | 0.97 |
+| `Mapster 10.0.7 (FEC)` | 1000000 | 124,374 us | 1,290 us | 2,466 us | 0.30 | 74000 | - | 1182.56 MB | 0.95 |
+| `Mapster 10.0.7 (Codegen)` | 1000000 | 105,214 us | 1,312 us | 2,206 us | 0.26 | 75500 | 166 | 1205.44 MB | 0.97 |
+| `AutoMapper 14.0.0` | 1000000 | 600,077 us | 63,170 us | 95,505 us | 1.45 | 197000 | 1000 | 3158.59 MB | 2.54 |
+| `Facet 6.5.5` | 1000000 | 628,280 us | 7,326 us | 11,076 us | 1.52 | 325000 | 1000 | 5187.99 MB | 4.17 |
+| `Mapperly 4.3.1` | 1000000 | 128,521 us | 1,453 us | 2,442 us | 0.31 | 94500 | 250 | 1510.62 MB | 1.21 |
 
 ### Step into debugging
 

diff --git a/docs/articles/packages/ExpressionDebugging.md b/docs/articles/packages/ExpressionDebugging.md
@@ -50,12 +50,8 @@ TypeAdapterConfig.GlobalSettings.Compiler = exp => exp.CompileWithDebugInfo(opt)
 var dto = poco.Adapt<SimplePoco, SimpleDto>(); //<-- you can step-into this function!!
 ```
 
-### Do not worry about performance
+### Performance notes
 
-In `RELEASE` mode, Roslyn compiler is actually faster than default dynamic compilation by 2x.
-Here is the result:
+In modern .NET runtimes, the Roslyn compiler path is mostly useful for step-into debugging and inspecting generated mapping code. In the current benchmark snapshot it performs close to the default Mapster compiler in steady-state execution.
 
-|                    Method |           Mean |       StdDev |        Error |       Gen 0 | Gen 1 | Gen 2 |  Allocated |
-|-------------------------- |---------------:|-------------:|-------------:|------------:|------:|------:|-----------:|
-|           'Mapster 4.1.1' | 115.31 ms | 0.849 ms | 1.426 ms | 31000.0000 |     - |     - | 124.36 MB |
-|  'Mapster 4.1.1 (Roslyn)' |  53.55 ms | 0.342 ms | 0.654 ms | 31100.0000 |     - |     - | 124.36 MB |
+See the [benchmark snapshot in README](../../../README.md#performance--memory-efficient) for current numbers.
diff --git a/docs/articles/packages/FastExpressionCompiler.md b/docs/articles/packages/FastExpressionCompiler.md
@@ -19,9 +19,11 @@ Then add following code on start up
 TypeAdapterConfig.GlobalSettings.Compiler = exp => exp.CompileFast();
 ```
 
-That's it. Now your code will enjoy performance boost. Here is result.
+That's it. Now your code will enjoy performance boost. Here is a current benchmark snapshot:
 
-|                    Method |           Mean |       StdDev |        Error |       Gen 0 | Gen 1 | Gen 2 |  Allocated |
-|-------------------------- |---------------:|-------------:|-------------:|------------:|------:|------:|-----------:|
-|           'Mapster 4.1.1' | 115.31 ms | 0.849 ms | 1.426 ms | 31000.0000 |     - |     - | 124.36 MB |
-|     'Mapster 4.1.1 (FEC)' |  54.70 ms | 1.023 ms | 1.546 ms | 29600.0000 |     - |     - | 118.26 MB |
+| Method | MapOperations | Mean | StdDev | Error | Ratio | Gen0 | Gen1 | Allocated | Alloc Ratio |
+| -------- | -------------- | -----: | -------: | ------: | ------: | -----: | -----: | ----------: | ----------: |
+| `Mapster 10.0.7` | 1000000 | 412,534 us | 2,704 us | 4,543 us | 1.00 | 77000 | - | 1243.59 MB | 1.00 |
+| `Mapster 10.0.7 (FEC)` | 1000000 | 124,374 us | 1,290 us | 2,466 us | 0.30 | 74000 | - | 1182.56 MB | 0.95 |
+
+See the [benchmark snapshot in README](../../../README.md#performance--memory-efficient) for the full comparison.
diff --git a/src/.editorconfig b/src/.editorconfig
@@ -1,4 +1,8 @@
-[*.cs]
+[*.{csproj,props}]
+indent_style = space
+indent_size = 2
+
+[*.cs]
 
 # S3220: Method calls should not resolve ambiguously to overloads with "params"
 dotnet_diagnostic.S3220.severity = suggestion

diff --git a/src/Benchmark.Development/Benchmark.Development.csproj b/src/Benchmark.Development/Benchmark.Development.csproj
@@ -3,14 +3,18 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net10.0</TargetFramework>
-	<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
-    <ImplicitUsings>enable</ImplicitUsings>
+    <LangVersion>12.0</LangVersion>
+
     <Nullable>enable</Nullable>
-    <SignAssembly>True</SignAssembly>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <RootNamespace>Mapster.Benchmark.Development</RootNamespace>
+
+    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <AssemblyOriginatorKeyFile>Benchmark.Development.snk</AssemblyOriginatorKeyFile>
+    <SignAssembly>True</SignAssembly>
     <DelaySign>False</DelaySign>
-	<SciVersion Condition="'$(SciVersion)' == ''">7.4.0</SciVersion>
-	<LangVersion>12.0</LangVersion>
+
+    <SciVersion Condition="'$(SciVersion)' == ''">7.4.0</SciVersion>
   </PropertyGroup>
 
   <ItemGroup>
@@ -21,17 +25,17 @@
   <ItemGroup>
     <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
   </ItemGroup>
-	<ItemGroup Condition="'$(Configuration)'=='Debug'">
-		<PackageReference Include="Mapster" Version="$(SciVersion)" />
-	</ItemGroup>
-	<ItemGroup Condition="'$(Configuration)'=='Release'">
-		<PackageReference Include="Mapster" Version="$(SciVersion)" />
-	</ItemGroup>
-	<ItemGroup Condition="'$(Configuration)'=='nuget-bench'">
-		<PackageReference Include="Mapster" Version="$(SciVersion)" />
-	</ItemGroup>
-	<ItemGroup Condition="'$(Configuration)'=='developer-bench'">
-		<ProjectReference Include="..\Mapster\Mapster.csproj" />
+  <ItemGroup Condition="'$(Configuration)'=='Debug'">
+    <PackageReference Include="Mapster" Version="$(SciVersion)" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(Configuration)'=='Release'">
+    <PackageReference Include="Mapster" Version="$(SciVersion)" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(Configuration)'=='nuget-bench'">
+    <PackageReference Include="Mapster" Version="$(SciVersion)" />
   </ItemGroup>
-
+  <ItemGroup Condition="'$(Configuration)'=='developer-bench'">
+    <ProjectReference Include="..\Mapster\Mapster.csproj" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/Benchmark.Development/Benchmarks/Config.cs b/src/Benchmark.Development/Benchmarks/Config.cs
@@ -1,14 +1,12 @@
-using Benchmark.Development;
-using BenchmarkDotNet.Columns;
+using BenchmarkDotNet.Columns;
 using BenchmarkDotNet.Configs;
 using BenchmarkDotNet.Diagnosers;
 using BenchmarkDotNet.Exporters;
 using BenchmarkDotNet.Exporters.Csv;
 using BenchmarkDotNet.Jobs;
 using BenchmarkDotNet.Loggers;
-using Perfolizer.Models;
 
-namespace Benchmark.Benchmarks
+namespace Mapster.Benchmark.Development.Benchmarks
 {
     public class Config : ManualConfig
     {
@@ -32,7 +30,7 @@ public Config()
 
             AddColumn(BaselineRatioColumn.RatioMean);
             AddColumnProvider(DefaultColumnProviders.Metrics);
-                              
+
 
 
             foreach (var version in MapsterVersion.Get())

diff --git a/src/Benchmark.Development/Benchmarks/TestAll.cs b/src/Benchmark.Development/Benchmarks/TestAll.cs
@@ -1,7 +1,7 @@
-using Benchmark.Classes;
-using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes;
+using Mapster.Benchmark.Development.Classes;
 
-namespace Benchmark.Benchmarks
+namespace Mapster.Benchmark.Development.Benchmarks
 {
     public class TestAll
     {

diff --git a/src/Benchmark.Development/Benchmarks/TestComplexTypes.cs b/src/Benchmark.Development/Benchmarks/TestComplexTypes.cs
@@ -1,7 +1,7 @@
-using Benchmark.Classes;
-using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes;
+using Mapster.Benchmark.Development.Classes;
 
-namespace Benchmark.Benchmarks
+namespace Mapster.Benchmark.Development.Benchmarks
 {
     public class TestComplexTypes
     {
@@ -15,7 +15,7 @@ public void MapsterTest()
         {
             TestAdaptHelper.TestMapsterAdapter<Customer, CustomerDTO>(_customerInstance, Iterations);
         }
-         
+
         [GlobalSetup(Target = nameof(MapsterTest))]
         public void SetupMapster()
         {

diff --git a/src/Benchmark.Development/Benchmarks/TestSimpleTypes.cs b/src/Benchmark.Development/Benchmarks/TestSimpleTypes.cs
@@ -1,7 +1,7 @@
-using Benchmark.Classes;
-using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes;
+using Mapster.Benchmark.Development.Classes;
 
-namespace Benchmark.Benchmarks
+namespace Mapster.Benchmark.Development.Benchmarks
 {
     public class TestSimpleTypes
     {
@@ -15,7 +15,7 @@ public void MapsterTest()
         {
             TestAdaptHelper.TestMapsterAdapter<Foo, Foo>(_fooInstance, Iterations);
         }
-        
+
         [GlobalSetup(Target = nameof(MapsterTest))]
         public void SetupMapster()
         {

diff --git a/src/Benchmark.Development/Classes/Customer.cs b/src/Benchmark.Development/Classes/Customer.cs
@@ -1,6 +1,4 @@
-using System.Collections.Generic;
-
-namespace Benchmark.Classes
+namespace Mapster.Benchmark.Development.Classes
 {
     public class Address
     {

diff --git a/src/Benchmark.Development/Classes/Foo.cs b/src/Benchmark.Development/Classes/Foo.cs
@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
-
-namespace Benchmark.Classes
+namespace Mapster.Benchmark.Development.Classes
 {
     public class Foo
     {

diff --git a/src/Benchmark.Development/MapsterVersion.cs b/src/Benchmark.Development/MapsterVersion.cs
@@ -1,12 +1,12 @@
-namespace Benchmark.Development
+namespace Mapster.Benchmark.Development
 {
     internal static class MapsterVersion
     {
 
         internal static string[] Get() =>
              [
                 "7.4.0",
-                "9.0.0-pre01"
+                "10.0.0"
              ];
     }
 }
diff --git a/src/Benchmark.Development/Program.cs b/src/Benchmark.Development/Program.cs
@@ -1,5 +1,5 @@
-using Benchmark.Benchmarks;
-using BenchmarkDotNet.Running;
+using BenchmarkDotNet.Running;
+using Mapster.Benchmark.Development.Benchmarks;
 
 var switcher = new BenchmarkSwitcher(new[]
             {

diff --git a/src/Benchmark.Development/TestAdaptHelper.cs b/src/Benchmark.Development/TestAdaptHelper.cs
@@ -1,12 +1,11 @@
-using Benchmark.Classes;
-using Mapster;
+using Mapster.Benchmark.Development.Classes;
 using System.Linq.Expressions;
 
-namespace Benchmark
+namespace Mapster.Benchmark.Development
 {
     public static class TestAdaptHelper
     {
-        
+
         public static Customer SetupCustomerInstance()
         {
             return new Customer
@@ -64,8 +63,8 @@ private static void SetupCompiler(MapsterCompilerType type)
             TypeAdapterConfig.GlobalSettings.Compiler = type switch
             {
                 MapsterCompilerType.Default => _defaultCompiler,
-               // MapsterCompilerType.Roslyn => exp => exp.CompileWithDebugInfo(),
-               // MapsterCompilerType.FEC => exp => exp.CompileFast(),
+                // MapsterCompilerType.Roslyn => exp => exp.CompileWithDebugInfo(),
+                // MapsterCompilerType.FEC => exp => exp.CompileFast(),
                 _ => throw new ArgumentOutOfRangeException(nameof(type)),
             };
         }
@@ -75,14 +74,14 @@ public static void ConfigureMapster(Foo fooInstance, MapsterCompilerType type)
             TypeAdapterConfig.GlobalSettings.Compile(typeof(Foo), typeof(Foo)); //recompile
             fooInstance.Adapt<Foo, Foo>(); //exercise
         }
-     
+
         public static void ConfigureMapster(Customer customerInstance, MapsterCompilerType type)
         {
             SetupCompiler(type);
             TypeAdapterConfig.GlobalSettings.Compile(typeof(Customer), typeof(CustomerDTO));    //recompile
             customerInstance.Adapt<Customer, CustomerDTO>();    //exercise
         }
-      
+
         public static void TestMapsterAdapter<TSrc, TDest>(TSrc item, int iterations)
             where TSrc : class
             where TDest : class, new()

diff --git a/src/Benchmark/Benchmark.csproj b/src/Benchmark/Benchmark.csproj
@@ -1,45 +1,54 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project Sdk="Microsoft.NET.Sdk">
-    <PropertyGroup>
-      <OutputType>Exe</OutputType>
-      <TargetFramework>net9.0</TargetFramework>
-      <CopyLocalLockFileAssemblies Condition=" '$(Configuration)'=='Debug' ">true</CopyLocalLockFileAssemblies>
-      <DefaultItemExcludes>**/*.g.cs</DefaultItemExcludes>
-    </PropertyGroup>
-    <ItemGroup>
-      <Compile Include="CustomerMapper.g.cs">
-        <DesignTime>True</DesignTime>
-        <AutoGen>True</AutoGen>
-        <DependentUpon>CustomerMapper.tt</DependentUpon>
-      </Compile>
-      <Compile Include="FooMapper.g.cs">
-        <DesignTime>True</DesignTime>
-        <AutoGen>True</AutoGen>
-        <DependentUpon>FooMapper.tt</DependentUpon>
-      </Compile>
-    </ItemGroup>
-    <ItemGroup>
-        <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
-        <PackageReference Include="ExpressionDebugger" Version="2.2.1" />
-        <PackageReference Include="ExpressionTranslator" Version="2.5.0" />
-        <PackageReference Include="FastExpressionCompiler" Version="5.3.0" />
-    </ItemGroup>
-    <ItemGroup>
-        <ProjectReference Include="..\ExpressionDebugger\ExpressionDebugger.csproj" />
-        <ProjectReference Include="..\ExpressionTranslator\ExpressionTranslator.csproj" />
-        <ProjectReference Include="..\Mapster\Mapster.csproj" />
-    </ItemGroup>
-    <ItemGroup>
-        <None Update="CustomerMapper.tt">
-            <Generator>TextTemplatingFileGenerator</Generator>
-            <LastGenOutput>CustomerMapper.g.cs</LastGenOutput>
-        </None>
-        <None Update="FooMapper.tt">
-            <Generator>TextTemplatingFileGenerator</Generator>
-            <LastGenOutput>FooMapper.g.cs</LastGenOutput>
-        </None>
-    </ItemGroup>
-    <ItemGroup>
-        <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" />
-    </ItemGroup>
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+
+    <RootNamespace>Mapster.Benchmark</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+
+    <CopyLocalLockFileAssemblies Condition=" '$(Configuration)'=='Debug' ">true</CopyLocalLockFileAssemblies>
+    <DefaultItemExcludes>**/*.g.cs</DefaultItemExcludes>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
+    <PackageReference Include="AutoMapper" Version="14.0.0" />
+    <PackageReference Include="Facet" Version="6.5.5" />
+    <PackageReference Include="FastExpressionCompiler" Version="5.4.1" />
+    <PackageReference Include="Riok.Mapperly" Version="4.3.1" ExcludeAssets="runtime" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ExpressionDebugger\ExpressionDebugger.csproj" />
+    <ProjectReference Include="..\ExpressionTranslator\ExpressionTranslator.csproj" />
+    <ProjectReference Include="..\Mapster\Mapster.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="CustomerMapper.g.cs">
+      <DesignTime>True</DesignTime>
+      <AutoGen>True</AutoGen>
+      <DependentUpon>CustomerMapper.tt</DependentUpon>
+    </Compile>
+    <Compile Include="FooMapper.g.cs">
+      <DesignTime>True</DesignTime>
+      <AutoGen>True</AutoGen>
+      <DependentUpon>FooMapper.tt</DependentUpon>
+    </Compile>
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="CustomerMapper.tt">
+      <Generator>TextTemplatingFileGenerator</Generator>
+      <LastGenOutput>CustomerMapper.g.cs</LastGenOutput>
+    </None>
+    <None Update="FooMapper.tt">
+      <Generator>TextTemplatingFileGenerator</Generator>
+      <LastGenOutput>FooMapper.g.cs</LastGenOutput>
+    </None>
+  </ItemGroup>
+
+  <ItemGroup>
+    <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" />
+  </ItemGroup>
 </Project>