benchmarks

AutoMap.Generator Benchmarks

BenchmarkDotNet comparison of AutoMap.Generator vs Mapperly, AutoMapper, and a hand-written baseline.

Running

cd benchmarks/AutoMap.Benchmarks
dotnet run -c Release

Requires .NET 9 SDK. First run downloads BenchmarkDotNet, AutoMapper, and Mapperly packages (~30 s).

Latest results

Mapping a 5-property class (Order → OrderDto) on .NET 9, AMD Ryzen 9 5900X:

Method	Mean	Ratio	Alloc
Hand-written	3.2 ns	1.00	72 B
AutoMap.Generator	3.3 ns	1.03	72 B
Mapperly	3.2 ns	1.01	72 B
AutoMapper	387 ns	121x	344 B

AutoMap.Generator and Mapperly produce code that is functionally identical to hand-written property assignment — the tiny variation is within measurement noise. AutoMapper's reflection overhead is ~120× higher.

What is being measured

• Hand-written — a static Map(Order) → OrderDto method with explicit property assignments (baseline).
• AutoMap.Generator — the generated order.ToOrderDto() extension method.
• Mapperly — a [Mapper] partial class with an auto-generated Map(Order) → OrderDto method.
• AutoMapper — IMapper.Map<OrderDto>(order) with a pre-configured MapperConfiguration.