performance-profiling

performance-profiling is a skill for Codex from devinilabs/pro-skill. It costs 69 tokens per session (1,287 once invoked), scanned A, a copy of performance-profiling, MIT.

A guide for measuring and diagnosing performance problems in Apple apps with Instruments, Xcode diagnostics, and MetricKit. It covers issues such as hangs, slow screens, high CPU use, memory leaks, battery drain, and slow launch.

In plain words
What is it for?
Use it when investigating freezes, stutters, memory growth, slow startup, energy use, thermal problems, or release-readiness performance.
Why use it?
It provides a method for choosing the right measurement tools and checking whether a change actually improves performance.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it when investigating freezes, stutters, memory growth, slow startup, energy use, thermal problems, or release-readiness performance.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/devinilabs/pro-skill/performance-profiling
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add devinilabs/pro-skill --skill performance-profiling
Clone the repo
git clone --depth 1 https://github.com/devinilabs/pro-skill

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for performance-profiling

README.md
[![agentmods](https://agentmods.dev/badge/skills/devinilabs/pro-skill/performance-profiling/github.svg)](https://agentmods.dev/skills/devinilabs/pro-skill/performance-profiling)
Your own site
<a href="https://agentmods.dev/skills/devinilabs/pro-skill/performance-profiling"><img src="https://agentmods.dev/badge/skills/devinilabs/pro-skill/performance-profiling/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for performance-profiling

Your own site · 80×15
<a href="https://agentmods.dev/skills/devinilabs/pro-skill/performance-profiling"><img src="https://agentmods.dev/badge/skills/devinilabs/pro-skill/performance-profiling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,287 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00069 $0.01287
Opus 5.5 $0.00028 $0.00515
Sonnet 5.5 $0.00014 $0.00257
Haiku 4.5 $0.00007 $0.00129

Measured 1mo ago against content hash e2301598090c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

performance-profiling scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to performance-profiling — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

agent-skills/codex/performance-profiling/SKILL.md · 150 lines

How it starts

The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Profiling

Use this skill to diagnose Apple app performance issues systematically, pick the right profiling workflow, apply targeted fixes, and verify the change with real measurements.

Decision Tree

Choose the reference file before changing code:

What performance problem are you investigating?

+ App hangs, stutters, dropped frames, slow UI, high CPU
  -> Read references/time-profiler.md

+ High memory, leaks, OOM crashes, growing footprint
  -> Read references/memory-profiling.md

+ Slow cold launch, warm launch, resume, or time to first frame
  -> Read references/launch-optimization.md

+ Battery drain, thermal throttling, background energy, network waste
  -> Read references/energy-diagnostics.md

+ General "app feels slow"
  -> Start with references/time-profiler.md, then references/memory-profiling.md

+ Pre-release performance audit
  -> Read all reference files and use the review checklist below

Quick Reference

Problem Instrument / Tool Key Metric Reference
UI hangs over 250 ms Time Profiler + Hangs Hang duration, main thread stack references/time-profiler.md
High CPU usage Time Profiler CPU percent by function, call tree weight references/time-profiler.md
Memory leak Leaks + Memory Graph Leaked bytes, retain cycle paths references/memory-profiling.md
Memory growth Allocations Live bytes, generation analysis references/memory-profiling.md
Slow launch App Launch Time to first frame, pre-main, post-main references/launch-optimization.md
Battery drain Energy Log Energy impact, CPU/GPU/network activity references/energy-diagnostics.md
Thermal issues Activity Monitor, Instruments Thermal state transitions references/energy-diagnostics.md
Network waste Network profiler Redundant fetches, payload size references/energy-diagnostics.md

Workflow

  1. Identify the performance category from the user report, traces, logs, or code path.
  2. Read only the matching reference file unless the issue is broad or unclear.
  3. Prefer real device profiling with a Release build and representative data.
  4. Inspect the code path named by the profile before proposing a fix.
  5. Apply the smallest targeted fix that addresses the measured bottleneck.
  6. Re-profile or add a repeatable measurement to confirm the improvement.

Read the full file on GitHub · 150 lines

Files

What ships with it

10 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 150 lines · 69 tokens per session scan A e2301598090c

Subscribe to this mod's changes

performance-profiling is a skill published in the GitHub repository devinilabs/pro-skill (28 stars, last pushed 2mo ago), licensed MIT. It adds 69 tokens to every session and 1,287 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to performance-profiling, differing in 0 lines, and is treated as a copy.