Function demo_performance

ci/examples/fingerprint_cache_demo.py:147–198

Demonstrate cache performance characteristics.

()

def demo_performance() -> None:
    """Demonstrate cache performance characteristics."""
    print("\n=== Performance Demo ===")

    with tempfile.TemporaryDirectory() as temp_dir:
        temp_path = Path(temp_dir)
        cache_file = temp_path / "perf_cache.json"
        cache = FingerprintCache(cache_file)

        # Create multiple test files
        num_files = 20
        test_files: list[Path] = []

        for i in range(num_files):
            test_file = temp_path / f"file_{i:03d}.cpp"
            with open(test_file, "w") as f:
                f.write(
                    f"// File {i}\n#include <iostream>\nint func_{i}() {{ return {i}; }}"
                )
            test_files.append(test_file)

        print(f"Created {num_files} test files")

        # Measure cache miss performance (first check)
        start_time = time.time()
        baseline_time = time.time() - 3600

        for test_file in test_files:
            cache.has_changed(test_file, baseline_time)

        miss_time = time.time() - start_time
        print(
            f"Cache miss time: {miss_time * 1000:.1f}ms ({miss_time * 1000 / num_files:.2f}ms per file)"
        )

        # Measure cache hit performance (second check with same modtime)
        modtimes = [os.path.getmtime(f) for f in test_files]

        start_time = time.time()
        for test_file, modtime in zip(test_files, modtimes):
            cache.has_changed(test_file, modtime)

        hit_time = time.time() - start_time
        print(
            f"Cache hit time: {hit_time * 1000:.1f}ms ({hit_time * 1000 / num_files:.2f}ms per file)"
        )
        print(f"Speedup: {miss_time / hit_time:.1f}x faster")

        # Show cache statistics
        stats = cache.get_cache_stats()
        print(f"Cache entries: {stats['total_entries']}")
        print(f"Cache file size: {stats['cache_file_size_bytes']} bytes")


def demo_convenience_function() -> None: