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Functorium

Reflection vs Source Generator

Compares reflection-based logging with the LoggerMessage.Define (source generator) approach.

Run

Section titled “Run”
Terminal window
dotnet run --project ReflectionVsSourceGen

FAQ

Section titled “FAQ”

Q1: How significant is the performance impact of reflection-based logging?

Section titled “Q1: How significant is the performance impact of reflection-based logging?”

A: Reflection queries type metadata on every call, which can result in a 100x or greater performance difference. In high-frequency call paths, GC pressure also increases, affecting overall application response time.

Q2: Why is LoggerMessage.Define high-performance?

Section titled “Q2: Why is LoggerMessage.Define high-performance?”

A: LoggerMessage.Define parses the log message template only once at compile time and caches it as a delegate. During logging calls, values are passed directly without string interpolation or boxing, resulting in zero allocations and high performance.

Q3: What preparation is needed to run this project?

Section titled “Q3: What preparation is needed to run this project?”

A: With the .NET SDK installed, you can run it immediately with the dotnet run --project ReflectionVsSourceGen command. Through the benchmark results, you can directly observe the performance difference between the reflection approach and the source generator approach.