Optimize
Benchmark, analyze, and optimize a function's execution time. Produces a before/after performance table with real numbers. Never presents a change without proving it is faster.From its SKILL.md
npx -y skills add v0idOS/performance-deity --skill optimizeAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
2 things to look at
- 2 stars2 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.
- runs commandsInstructs the agent to run 3 commands, including `Run the script using the terminal.` and 2 more.
SKILL.md
2.1 KB, 455 tokens by cl100k_base, as published. Nobody here has run it
Execute all four phases in order. Do not skip any phase.
Phase 1 — Establish Baseline
- Identify the exact code to optimize.
- Run a micro-benchmark:
- Write a temporary micro-benchmark script in the user's workspace.
- The script MUST contain a warm-up phase (discard ≥10 iterations).
- The script MUST run ≥100 iterations and output the Average and P95 execution time.
- Run the script using the terminal.
- Delete the temporary script after recording the results.
- Note: If the script fails due to missing imports or dependencies, skip it and use the bash
timecommand as a fallback.
- Record P95 and Average. Do not proceed until the benchmark runs without error.
- Report baseline numbers before writing any new code.
Phase 2 — Algorithmic Analysis
- State the current Time Complexity (Big-O) explicitly.
- State the current Space Complexity and identify the primary allocation sites.
- Name the bottleneck precisely:
- "Nested loops causing O(n²) scaling"
- "Repeated string concatenation causing N heap allocations per call"
- "Full table scan caused by missing index on
user_id"
Phase 3 — Refactoring
- Rewrite using a more efficient algorithm or data structure (apply in priority order):
- Replace Array/List lookups with Hash Sets/Dictionaries: O(N) → O(1)
- Vectorization or batching instead of per-item iteration
- Caching/memoization of expensive pure computations
- Zero-allocation patterns and buffer reuse to reduce GC pressure
- Bitwise operations where mathematically equivalent
- Run the benchmark on the new code.
- If the new code is not measurably faster: discard it, select a different approach, repeat.
Phase 4 — Report
Present a Performance Report table:
| Metric | Baseline | Optimized | Δ |
|---|---|---|---|
| Average | Xms | Yms | -Z% |
| P95 | Xms | Yms | -Z% |
Follow with a one-paragraph explanation grounded in CPU/memory theory.
What ships with it
Read from the repository
Just SKILL.md. No reference files, no scripts.