build-perf-baseline

Measure three scenarios: a cold build after deleting bin/obj folders, a warm build after touching one source file, and a no-op build with no changes. Use dotnet build with the /bl flag to capture binary logs for each scenario.

Start by baselining cold, warm, and no-op builds, then apply targeted fixes: enable MSBuild Server, use UseArtifactsOutput, trim redundant ProjectReferences, try static graph builds with /graph, and tune parallelism with -m. Separate restore from build in CI pipelines.

A no-op build should finish in under 5 seconds for small repos and under 30 seconds for large repos, with all compilation targets reporting up-to-date. If it exceeds 30 seconds, incremental build is broken and needs Inputs/Outputs fixes.

Use /graph for large solutions with 20 or more projects and in CI, where upfront graph evaluation improves scheduling and parallelism. Avoid it for small solutions under 5 projects, where graph evaluation overhead outweighs the benefits.

Full recompilation on warm builds usually means the project dependency chain forces cascading rebuilds. Remove redundant transitive ProjectReferences, use ReferenceOutputAssembly="false" for build-order-only dependencies, and check incremental build Inputs/Outputs configuration.