Mcaf Dotnet Profiling

MCAF: .NET Profiling

Trigger On

• the repo needs performance or runtime profiling for a .NET application
• the user asks about slow code, high CPU, GC pressure, allocation growth, exception storms, lock contention, or startup diagnostics
• the team wants official CLI-based diagnostics without depending on dnx

Value

• produce a concrete project delta: code, docs, config, tests, CI, or review artifact
• reduce ambiguity through explicit planning, verification, and final validation skills
• leave reusable project context so future tasks are faster and safer

Do Not Use For

• replacing realistic performance tests or load tests with ad-hoc tracing alone
• production heap collection when the pause risk has not been accepted
• GUI-only workflows that the repo cannot automate or document

Inputs

• the nearest AGENTS.md
• target application, process, or startup path
• the symptom being investigated: CPU, memory, GC, contention, exceptions, or startup

Quick Start

1. Read the nearest AGENTS.md and confirm scope and constraints.
2. Run this skill's Workflow through the Ralph Loop until outcomes are acceptable.
3. Return the Required Result Format with concrete artifacts and verification evidence.

Workflow

1. Build and run a realistic target first:
   • prefer Release
   • prefer realistic config, inputs, and data volume
2. Start with the lightest useful tool:
   • dotnet-counters for live health signals
   • dotnet-trace for CPU, exception, contention, GC, and startup traces
   • dotnet-gcdump for managed heap inspection when memory shape matters
3. Prefer installed CLI tools over dnx one-shot execution so the repo commands stay stable and reproducible.
4. Capture one focused profile at a time instead of mixing every signal into one run.
5. For CPU and general runtime hotspots, start with dotnet-trace collect.
6. For live triage, start with dotnet-counters monitor on System.Runtime.
7. For heap analysis, use dotnet-gcdump carefully and document the pause risk.
8. After each change, rerun the same measurement path and compare before versus after.

Bootstrap When Missing

If official .NET profiling tools are not available yet:

1. Detect current state:
   • dotnet --info
   • dotnet tool list --global
   • command -v dotnet-counters
   • command -v dotnet-trace
   • command -v dotnet-gcdump
2. Choose the install path deliberately:
   • preferred machine-level install:
     • dotnet tool install --global dotnet-counters
     • dotnet tool install --global dotnet-trace
     • dotnet tool install --global dotnet-gcdump
   • direct-download fallback when global tools are not suitable:
     • use the official Microsoft Learn download links for dotnet-counters, dotnet-trace, and dotnet-gcdump
3. Verify the installed tools resolve correctly:
   • dotnet-counters --version
   • dotnet-trace --version
   • dotnet-gcdump --version
4. Record exact profiling commands in AGENTS.md, for example:
   • dotnet-counters monitor --process-id PID --counters System.Runtime
   • dotnet-trace collect --process-id PID --profile dotnet-common,dotnet-sampled-thread-time -o trace.nettrace
   • dotnet-gcdump collect --process-id PID --output heap.gcdump
5. Run one bounded command and return status: configured or status: improved.
6. If the repo intentionally standardizes on another profiling stack and does not want these tools, return status: not_applicable.