eval-performance

MSBuild Evaluation Phases

For a comprehensive overview of MSBuild's evaluation and execution model, see Build process overview.

1. Initial properties: environment variables, global properties, reserved properties
2. Imports and property evaluation: process <Import>, evaluate <PropertyGroup> top-to-bottom
3. Item definition evaluation: <ItemDefinitionGroup> metadata defaults
4. Item evaluation: <ItemGroup> with Include, Remove, Update, glob expansion
5. UsingTask evaluation: register custom tasks

Key insight: evaluation happens BEFORE any targets run. Slow evaluation = slow build start even when nothing needs compiling.

Diagnosing Evaluation Performance

Using binlog

1. Replay the binlog: dotnet msbuild build.binlog -noconlog -fl -flp:v=diag;logfile=full.log
2. Search for evaluation events: grep -i 'Evaluation started\|Evaluation finished' full.log
3. Multiple evaluations for the same project = overbuilding