performance-investigation
Investigate performance regressions and find opportunities for optimization
- Installs
- 150
- Last 24h
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- Trending rank
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- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/sveltejs/svelte --skill performance-investigation- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads performance-investigation automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Quick start
- Start from a branch you want to measure (for example
foo). - Run:
pnpm bench:compare main foo
If you pass one branch, bench:compare automatically compares it to main.
Where outputs go
- Summary report:
benchmarking/compare/.results/report.txt - Raw benchmark numbers:
benchmarking/compare/.results/main.jsonbenchmarking/compare/.results/<your-branch>.json
- CPU profiles (per benchmark, per branch):
benchmarking/compare/.profiles/main/*.cpuprofilebenchmarking/compare/.profiles/main/*.mdbenchmarking/compare/.profiles/<your-branch>/*.cpuprofilebenchmarking/compare/.profiles/<your-branch>/*.md
The .md files are generated summaries of the CPU profile and are usually the fastest way to inspect hotspots.
Suggested investigation flow
- Open
benchmarking/compare/.results/report.txtand identify largest regressions first. - For each high-delta benchmark, compare:
benchmarking/compare/.profiles/main/<benchmark>.mdbenchmarking/compare/.profiles/<branch>/<benchmark>.md
- Look for changes in self/inclusive hotspot share in runtime internals (
runtime.js,reactivity/batch.js,reactivity/deriveds.js,reactivity/sources.js). - Make one optimization change at a time, then re-run targeted benches before re-running full compare.
Fast benchmark loops
Run only selected reactivity benchmarks by substring:
pnpm bench kairo_mux kairo_deep kairo_broad kairo_triangle
pnpm bench repeated_deps sbench_create_signals mol_owned
Tests to run after perf changes
Runtime reactivity regressions are most likely in runes runtime tests:
pnpm test runtime-runes
Helpful script
For quick cpuprofile hotspot deltas between two branches:
node benchmarking/compare/profile-diff.mjs kairo_mux_owned main foo
This prints top function sample-share deltas for the selected benchmark.
Practical gotchas
bench:comparechecks out branches while running. Avoid uncommitted changes (or stash them) so branch switching is safe.- Each
bench:comparerun rewritesbenchmarking/compare/.resultsandbenchmarking/compare/.profiles.
FAQ
What does the performance-investigation skill do?
Investigate performance regressions and find opportunities for optimization
How do I install performance-investigation?
Run npx skills add https://github.com/sveltejs/svelte --skill performance-investigation in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/performance-investigation/ (personal) or .claude/skills/performance-investigation/ (project).
Which AI agents can use performance-investigation?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is performance-investigation safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains performance-investigation?
It is published by sveltejs in sveltejs/svelte, and it is an official skill from the maker of the technology it covers. It has 150 recorded installs.
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