build-performance-analysis

name	build-performance-analysis
description	Analyze MSBuild build performance and find bottlenecks using binlog-insights MCP tools. Use when a build is slow, you need to optimize build times, or identify expensive projects, targets, tasks, or Roslyn analyzers. Also triggers for build duration, build speed, and compilation time.
metadata	{"traits":"MSBuild|DotNet|CSharp|Build|Binlog|Performance"}

Build Performance Analysis

Overview

Find what's making an MSBuild build slow by analyzing .binlog files. Identifies expensive projects, targets, tasks, and Roslyn analyzers using binlog-insights MCP tools.

Quick Start

dotnet build /bl:build.binlog

Then ask: "Why is my build slow? Analyze build.binlog performance."

Workflow

1. Run binlog_overview to get total build duration and project count
2. Run binlog_expensive_projects to find the slowest projects
3. For each slow project, run binlog_project_target_times to see which targets take the most time
4. Run binlog_expensive_targets for a build-wide view of the slowest targets
5. Run binlog_expensive_tasks to find the most expensive individual tasks
6. Run binlog_expensive_analyzers to check if Roslyn analyzers are a bottleneck
7. For suspicious targets, use binlog_tasks_in_target and binlog_task_details to inspect what they do

Task Progress:
- [ ] Step 1: binlog_overview — total duration
- [ ] Step 2: binlog_expensive_projects — slowest projects
- [ ] Step 3: binlog_project_target_times — target breakdown per project
- [ ] Step 4: binlog_expensive_targets — global target hotspots
- [ ] Step 5: binlog_expensive_tasks — global task hotspots
- [ ] Step 6: binlog_expensive_analyzers — analyzer impact
- [ ] Step 7: Deep dive into suspicious targets

Tool Reference

Tool	Purpose
binlog_overview	Build status, duration, project count
binlog_expensive_projects	Slowest projects by duration
binlog_project_target_times	Target timing for a specific project
binlog_expensive_targets	Slowest targets across all projects
binlog_expensive_tasks	Slowest tasks across all projects
binlog_expensive_analyzers	Roslyn analyzer performance
binlog_tasks_in_target	Tasks within a specific target
binlog_task_details	Details of a specific task execution
binlog_projects	Project list with status and duration

Common Patterns

Slow build — find the bottleneck: Action: binlog_expensive_projects → find 60s project → binlog_project_target_times → discover ResolveAssemblyReference takes 45s

Analyzer overhead: Action: binlog_expensive_analyzers → find analyzer taking 15s per project → disable or move to CI-only

Unexpected target running: Action: binlog_expensive_targets → spot GenerateNuspec running for 30 projects that don't ship packages → check IsPackable property

Troubleshooting

• No binlog file: Rebuild with dotnet build /bl:build.binlog
• Tool not found: Ensure binlog-insights-mcp is installed: dotnet tool install -g BinlogInsights.Mcp
• Filter to one project: Use --project <substring> on any tool to narrow results