Performance Profiler

This skill guides the agent through systematic latency and resource bottleneck profiling.

Profiling Workflow

1. Identify the Bottleneck Metric

Determine the performance symptom:

• High CPU: Algorithmic complexity ($O(n^2)$), tight loops, excessive JSON serialization.
• High Memory / Leak: Retained closures, unclosed database streams, unbounded in-memory caches.
• High Latency (I/O): N+1 database queries, unindexed SQL lookups, synchronous blocking disk I/O.

2. Node.js & V8 Profiling

Run Node with the V8 sampling profiler:

node --prof app.js
node --prof-process isolate-*.log > processed.txt

3. Database Query Analysis

• PostgreSQL: Run EXPLAIN (ANALYZE, BUFFERS) <query> to inspect sequential scans, join types, and execution time.
• Indexes: Verify that high-cardinality WHERE and JOIN columns have appropriate B-Tree or Hash indexes.

4. Memory Heap Dumps

Capture heap snapshots or track memory diffs between iterations to isolate leaks:

const mem = process.memoryUsage();
console.log(`Heap Used: ${Math.round(mem.heapUsed / 1024 / 1024)} MB`);