Docs/cookbook/performance/README

Performance Engineering Cookbook

Version: 1.1.0 | Updated: 2026-07-16

Purpose

Operate AI-assisted changes to a SLO, workload model, benchmark, profile, capacity plan, Web Vital budget, or regression gate using Performance Engineering's native contracts, commands, failure evidence, architecture, and rollback mechanisms.

Why

Optimization starts from a reproducible workload and user-impact metric; profiles identify the limiting resource; CI and production enforce budgets. Generic software advice cannot verify that invariant because the decisive evidence lives in SLI/SLO definition, histogram boundaries, trace sampling, RUM attribution, and business-impact cohort; workload script, request/data distribution, concurrency/arrival model, warmup, repetitions, and raw results; CPU, allocation/heap, I/O, lock, network, database, and browser trace aligned to one run.

How

  1. Supply the evidence below to the matching XML prompt.
  2. Execute the skill's native workflow rather than accepting prose-only output.
  3. Use the error workflow to classify observed failure before changing state.
  4. Preserve architecture boundaries in architecture/patterns.md.
  5. Block review or release on any unchecked technology gate.

Required evidence

  • SLI/SLO definition, histogram boundaries, trace sampling, RUM attribution, and business-impact cohort
  • workload script, request/data distribution, concurrency/arrival model, warmup, repetitions, and raw results
  • CPU, allocation/heap, I/O, lock, network, database, and browser trace aligned to one run
  • baseline/candidate confidence, effect size, noise controls, capacity saturation, and cost per operation

Native verification

  • run the repository's load test with a versioned scenario and export raw results
  • npx lighthouse <url> --output=json --output-path=lighthouse.json for controlled web lab evidence
  • node --prof / JFR / dotnet-trace / py-spy only when matching the measured runtime
  • capture Chrome DevTools Performance trace with production build and defined network/CPU conditions
  • query production histograms and traces by release/cohort; never average percentiles

Version-aware caution

Record hardware, OS/kernel, runtime/browser, build mode, dependency versions, dataset, network shaping, cache state, and measurement tool version. Results from different environments or metric definitions are not comparable.

Tradeoffs

This cookbook requires deeper Performance Engineering evidence and specialist review than a generic template. The additional work buys reproducible diagnostics and a rollback that respects SLO, workload model, benchmark, profile, capacity plan, Web Vital budget, or regression gate state.

Anti-patterns

  • Optimizing a local microbenchmark without production distribution or profile evidence moves code while leaving the system bottleneck unchanged.
  • Do not remove a native warning, validator, policy, or safety limit merely to make generated output pass.
  • Do not claim a successful result without preserving the command, target, artifact/revision, and observed output.

Enterprise considerations

Performance governance standardizes metric definitions, benchmark hardware, raw-result retention, RUM privacy, SLO ownership, exception expiry, and capacity-review cadence.

Official sources

Checklist

  • Installed/deployed version and target environment are recorded.
  • Native commands are selected from repository and platform evidence.
  • Failure classes and rollback boundary are explicit.
  • Official sources are checked for the recorded version.
  • No prompt variable remains unresolved.

Changelog

  • 1.1.0 (2026-07-16): Replaced cloned guidance with technology-native evidence, commands, architecture, and rollback.
  • 1.0.0 (2026-07-16): Added initial cookbook.