Benchmark
Turns "it feels faster" into "p99 reduced by 40ms under 200 RPS." Benchmarking provides the empirical evidence required to validate performance ACs.
Why this skill exists
Performance claims are often "vibes-based" or measured on a developer's machine without a recorded baseline. This skill ensures performance data is reproducible and comparable.
When to use
- Verifying performance-related Acceptance Criteria in a feature doc.
- Identifying regressions or improvements after a major refactor.
- Profiling hot paths to guide optimization.
Process
1. Establish Baseline
Measure the performance of the code before the change. Record the environment (hardware, load, concurrency).
2. Execute Benchmark
Run the same test against the changed code. Ensure identical environment conditions.
3. Record Findings
Create a report in docs/benchmarks/<feature>.md using the template.
Done when
- A benchmark report exists in
docs/benchmarks/. - Baseline and current measurements are clearly compared.
- The environment and load profile are documented.