performance

Diagnose and remediate performance bottlenecks in Juju charm hooks and relations.

1|Updated Feb 8, 2026

Search Tags:#performance #profiling #charm #timeout #hook #juju #pebble

Ready to run

npx skills add https://github.com/tonyandrewmeyer/cantrip --skill performance-tonyandrewmeyer

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: performance
Source: https://github.com/tonyandrewmeyer/cantrip/tree/main/src/cantrip/skills/performance
Command: npx skills add https://github.com/tonyandrewmeyer/cantrip --skill performance-tonyandrewmeyer

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Juju charms sometimes suffer from performance bottlenecks such as slow hook handlers, excessive polling, and large data payloads. This skill identifies and fixes common performance issues to keep charms responsive and reliable.

Core Features & Use Cases

Detect blocking I/O in hook handlers and propose asynchronous or deferred executions.
Reduce update-status and relation-changed overhead with caching, lightweight checks, and Pebble health hints.
Minimize payload sizes and optimize Pebble interactions to stabilize charm lifecycles.
Use profiling tools (Tempo, juju_debug_log) to identify bottlenecks and validate fixes.

Quick Start

Run a performance diagnostic on your charm to identify slow hooks and optimization opportunities.

Frequently Asked Questions about performance

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I diagnose slow hook execution in Juju charms?▼

Diagnose slow Juju charm hook execution by profiling with Tempo and juju_debug_log to identify bottlenecks, then apply caching, timeouts on external calls, and asynchronous execution to optimize performance.

Why does my Juju relation-changed hook have high execution overhead?▼

High relation-changed hook overhead in Juju often stems from excessive polling and large data payloads. Reduce this overhead by implementing caching, lightweight health checks, and Pebble health hints to stabilize charm lifecycles.

What's the best way to fix blocking I/O in Juju Pebble interactions?▼

Fix blocking I/O in Juju Pebble interactions by enforcing timeouts on external calls, applying data-size limits, and proposing asynchronous or deferred executions to ensure rapid and reliable charm execution.

How do I profile a Juju charm to find performance bottlenecks?▼

Profile Juju charm performance bottlenecks using Tempo and juju_debug_log. These tools identify slow hooks and optimization opportunities across install, config-changed, and update-status events.

Can I use caching to reduce update-status hook overhead in Juju?▼

Yes, you can use caching to reduce update-status hook overhead in Juju. Implementing caching alongside lightweight checks and Pebble health hints minimizes payload sizes and stabilizes charm lifecycles.

What causes performance bottlenecks in Juju charms during config-changed events?▼

Performance bottlenecks during Juju config-changed events are caused by blocking I/O, excessive polling, and large data payloads. Enforce timeouts, minimize payload sizes, and optimize Pebble interactions to resolve them.