name: libperf description: > libperf - Performance testing utilities. benchmark function measures execution time and memory. validateDuration and validateMemory assert performance constraints. ScalingAnalyzer detects linear vs sublinear scaling. PerfRunner orchestrates benchmark suites. Use for performance testing, benchmarking, and detecting performance regressions.

libperf Skill

When to Use

• Writing performance tests for critical code paths
• Benchmarking function execution time and memory
• Detecting performance regressions in CI
• Validating scaling characteristics (O(n) vs O(n²))

Key Concepts

benchmark: Runs a function multiple times and collects timing/memory stats.

validateDuration/validateMemory: Assert that benchmarks meet performance requirements.

ScalingAnalyzer: Analyzes how performance scales with input size.

Usage Patterns

Pattern 1: Basic benchmark

import { benchmark, validateDuration } from "@copilot-ld/libperf";

const result = await benchmark(
  async () => {
    await myFunction(input);
  },
  { iterations: 100 },
);

validateDuration(result, 50); // Assert max 50ms

Pattern 2: Scaling analysis

import { ScalingAnalyzer } from "@copilot-ld/libperf";

const analyzer = new ScalingAnalyzer();
const scaling = await analyzer.analyze(fn, [100, 1000, 10000]);
// scaling.type: "linear" | "sublinear" | "superlinear"

Integration

Performance tests use .perf.js extension. Run via npm run test:perf.