configurable scan parallelism based on hdd or sdd

backend/library/metrics.go

@@ -0,0 +1,103 @@
+package library
+
+import (
+	"sync"
+	"time"
+)
+
+// ScanMetrics holds timing and count data collected during a library scan.
+// Worker-pool fields are protected by a mutex; DB-writer fields are
+// single-threaded and use plain addition.
+type ScanMetrics struct {
+	mu sync.Mutex
+
+	// Top-level phases (wall-clock).
+	Total               time.Duration `json:"total"`
+	LoadExisting        time.Duration `json:"loadExisting"`
+	WalkDuration        time.Duration `json:"walkDuration"`
+	ExtractionWallClock time.Duration `json:"extractionWallClock"`
+	DBWritesWallClock   time.Duration `json:"dbWritesWallClock"`
+	OrphanCleanup       time.Duration `json:"orphanCleanup"`
+	PostScanVariants    time.Duration `json:"postScanVariants"`
+
+	// Per-format extraction (cumulative across workers).
+	FormatExtraction map[string]int64 `json:"formatExtraction"`
+	FormatCount      map[string]int64 `json:"formatCount"`
+
+	// Sub-operation cumulative times (across workers).
+	TagExtraction      time.Duration `json:"tagExtraction"`
+	DurationExtraction time.Duration `json:"durationExtraction"`
+
+	// DB sub-operations (cumulative, single-threaded DB writer).
+	BatchCommits time.Duration `json:"batchCommits"`
+	CoverArtSave time.Duration `json:"coverArtSave"`
+
+	// Thumbnail generation (async worker pool).
+	ThumbnailWallClock  time.Duration `json:"thumbnailWallClock"`
+	ThumbnailGeneration time.Duration `json:"thumbnailGeneration"`
+	ThumbnailSmall      time.Duration `json:"thumbnailSmall"`
+	ThumbnailMedium     time.Duration `json:"thumbnailMedium"`
+	ThumbnailLarge      time.Duration `json:"thumbnailLarge"`
+
+	// Full-rescan-specific phases.
+	ClearQueue      time.Duration `json:"clearQueue"`
+	ClearDatabase   time.Duration `json:"clearDatabase"`
+	ClearCoverFiles time.Duration `json:"clearCoverFiles"`
+
+	// File counts.
+	Added   int64 `json:"added"`
+	Updated int64 `json:"updated"`
+	Skipped int64 `json:"skipped"`
+	Removed int64 `json:"removed"`
+}
+
+func newScanMetrics() *ScanMetrics {
+	return &ScanMetrics{
+		FormatExtraction: make(map[string]int64),
+		FormatCount:      make(map[string]int64),
+	}
+}
+
+// addExtraction records per-file extraction timing from a worker
+// goroutine.  It is safe for concurrent use.
+func (m *ScanMetrics) addExtraction(
+	fileType string,
+	tagTime, durationTime time.Duration,
+) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	total := tagTime + durationTime
+	m.FormatExtraction[fileType] += total.Milliseconds()
+	m.FormatCount[fileType]++
+	m.TagExtraction += tagTime
+	m.DurationExtraction += durationTime
+}
+
+// addCoverArtSave records the time spent saving an original cover
+// art file.  Called from the single-threaded DB writer.
+func (m *ScanMetrics) addCoverArtSave(d time.Duration) {
+	m.CoverArtSave += d
+}
+
+// addThumbnailTier records the time spent generating a single
+// thumbnail tier.  Safe for concurrent use from the thumbnail
+// worker pool.
+func (m *ScanMetrics) addThumbnailTier(
+	suffix string,
+	d time.Duration,
+) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.ThumbnailGeneration += d
+
+	switch suffix {
+	case "_sm":
+		m.ThumbnailSmall += d
+	case "_md":
+		m.ThumbnailMedium += d
+	case "_lg":
+		m.ThumbnailLarge += d
+	}
+}