AutoMapper is undoubtedly the most popular object to object mapping library used around and it wouldn’t be a surprise to know if any of us, including yours truly, have even tried out alternatives. I recently tried out Mapster and was quite surprised by the results. Even they did mention their Github pages about being faster than Automapper, I honestly didn’t believe the performance difference until I saw it myself. And truly, I am impressed.
I ran a couple of tests with the following models.
public class SimpleObjectSource
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Department { get; set; }
}
public class SimpleObjectDestination
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Department { get; set; }
}
public class ComplexObjectSource
{
public int Id { get; set; }
public IEnumerable<int> Values { get; set; }
public List<ComplexObjectSource> ComplexCollection { get; set; }
}
public class ComplexObjectDestination
{
public int Id { get; set; }
public IEnumerable<int> Values { get; set; }
public List<ComplexObjectDestination> ComplexCollection { get; set; }
}
With the models defined above, I create a few Benchmark tests which could compare the mapping performance when mapping individual entity as well as when mapping collections of the entities. Following were the Benchmark Results I got when mapping single entities.
| Method | Mean | Error | StdDev | Median |
|----------------------------------------- |--------------:|-------------:|-------------:|--------------:|
| SingleEntitySimpleObjectUsingAutomapper | 162.53 ns | 14.191 ns | 40.027 ns | 141.16 ns |
| SingleEntitySimpleObjectUsingMapster | 45.40 ns | 0.907 ns | 1.726 ns | 45.15 ns |
| SingleEntityComplexObjectUsingAutomapper | 152,409.98 ns | 2,966.145 ns | 2,913.151 ns | 151,781.99 ns |
| SingleEntityComplexObjectUsingMapster | 5,290.26 ns | 76.098 ns | 63.545 ns | 5,298.70 ns |
While following were the results when mapping collections
| Method | Mean | Error | StdDev |
|--------------------------------- |--------------:|-------------:|--------------:|
| SimpleCollectionUsingAutomapper | 24.00 us | 0.472 us | 0.614 us |
| SimpleCollectionUsingMapster | 18.60 us | 0.499 us | 1.456 us |
| ComplexCollectionUsingAutomapper | 343,087.60 us | 6,768.516 us | 15,277.668 us |
| ComplexCollectionUsingMapster | 45,739.96 us | 905.842 us | 2,479.728 us |
As one can observe there are huge performance benefits with the Mapster implementation. I am not quite sure if this is a fair comparison though, as these tests only compare the performance on certain conditions, and do not consider the overall functionality provided by the library. Maybe I will compare the functionality on a separate blog. But for the performance under the particular conditions, I am pretty impressed by Mapster even though I had been using AutoMapper whole my life for mapping.
ByteLanguage.Net 