fetch_ml/tests/benchmarks/dataset_hash_bench_test.go
Jeremie Fraeys 72b4b29ecd
perf: add profiling benchmarks and parallel Go baseline for C++ optimization
Add comprehensive benchmarking suite for C++ optimization targets:
- tests/benchmarks/dataset_hash_bench_test.go - dirOverallSHA256Hex profiling
- tests/benchmarks/queue_bench_test.go - filesystem queue profiling
- tests/benchmarks/artifact_and_snapshot_bench_test.go - scanArtifacts/extractTarGz profiling
- tests/unit/worker/artifacts_test.go - moved from internal/ for clean separation

Add parallel Go implementation as baseline for C++ comparison:
- internal/worker/data_integrity.go: dirOverallSHA256HexParallel() with worker pool
- Benchmarks show 2.1x speedup (3.97ms -> 1.90ms) vs sequential

Exported wrappers for testing:
- ScanArtifacts() - artifact scanning
- ExtractTarGz() - tar.gz extraction
- DirOverallSHA256HexParallel() - parallel hashing

Profiling results (Apple M2 Ultra):
- dirOverallSHA256Hex: 78% syscall overhead (target for mmap C++)
- rebuildIndex: 96% syscall overhead (target for binary index C++)
- scanArtifacts: 87% syscall overhead (target for fast traversal C++)
- extractTarGz: 95% syscall overhead (target for parallel gzip C++)

Related: C++ optimization strategy in memory 5d5f0bb6
2026-02-12 12:04:02 -05:00

105 lines
2.5 KiB
Go

package benchmarks
import (
"os"
"path/filepath"
"testing"
"github.com/jfraeys/fetch_ml/internal/worker"
)
// BenchmarkDirOverallSHA256Hex profiles the directory hashing hot path.
// This function walks directories, sorts files, and computes SHA256 hashes.
// It's a Tier 1 candidate for C++ optimization via:
// - Memory-mapped file reads
// - Parallel hashing
// - SIMD SHA256 (Intel SHA extensions or ARMv8 crypto)
func BenchmarkDirOverallSHA256Hex(b *testing.B) {
// Create a temp directory structure resembling a dataset
tmpDir := b.TempDir()
// Create nested structure with files of varying sizes
sizes := []int{1024, 10240, 102400, 1024 * 1024} // 1KB to 1MB
for i, size := range sizes {
subdir := filepath.Join(tmpDir, "subdir", string(rune('a'+i)))
if err := os.MkdirAll(subdir, 0750); err != nil {
b.Fatal(err)
}
data := make([]byte, size)
for j := range data {
data[j] = byte(i + j%256)
}
if err := os.WriteFile(filepath.Join(subdir, "data.bin"), data, 0640); err != nil {
b.Fatal(err)
}
}
// Add some small metadata files
metaDir := filepath.Join(tmpDir, "meta")
if err := os.MkdirAll(metaDir, 0750); err != nil {
b.Fatal(err)
}
for i := 0; i < 10; i++ {
if err := os.WriteFile(
filepath.Join(metaDir, "file"+string(rune('0'+i))+".json"),
[]byte(`{"key": "value"}`),
0640,
); err != nil {
b.Fatal(err)
}
}
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, err := worker.DirOverallSHA256Hex(tmpDir)
if err != nil {
b.Fatal(err)
}
}
}
// BenchmarkDirOverallSHA256HexLarge profiles with larger dataset simulation
func BenchmarkDirOverallSHA256HexLarge(b *testing.B) {
tmpDir := b.TempDir()
// Create 50 files of 100KB each = ~5MB total
for i := 0; i < 50; i++ {
subdir := filepath.Join(tmpDir, "data", string(rune('a'+i%26)))
if err := os.MkdirAll(subdir, 0750); err != nil {
b.Fatal(err)
}
data := make([]byte, 100*1024)
for j := range data {
data[j] = byte(i + j%256)
}
if err := os.WriteFile(
filepath.Join(subdir, "chunk"+string(rune('0'+i/26))+".bin"),
data,
0640,
); err != nil {
b.Fatal(err)
}
}
b.Run("Sequential", func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, err := worker.DirOverallSHA256Hex(tmpDir)
if err != nil {
b.Fatal(err)
}
}
})
b.Run("ParallelGo", func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, err := worker.DirOverallSHA256HexParallel(tmpDir)
if err != nil {
b.Fatal(err)
}
}
})
}