wip

lib/logstorage/bitmap.go

@@ -146,6 +146,28 @@ func (bm *bitmap) forEachSetBit(f func(idx int) bool) {
 	}
 }
 
+// forEachSetBitReadonly calls f for each set bit
+func (bm *bitmap) forEachSetBitReadonly(f func(idx int)) {
+	a := bm.a
+	bitsLen := bm.bitsLen
+	for i, word := range a {
+		if word == 0 {
+			continue
+		}
+		for j := 0; j < 64; j++ {
+			mask := uint64(1) << j
+			if (word & mask) == 0 {
+				continue
+			}
+			idx := i*64 + j
+			if idx >= bitsLen {
+				break
+			}
+			f(idx)
+		}
+	}
+}
+
 func (bm *bitmap) onesCount() int {
 	n := 0
 	for _, word := range bm.a {

lib/logstorage/bitmap_test.go

@@ -32,7 +32,7 @@ func TestBitmap(t *testing.T) {
 
 		// Make sure that all the bits are set.
 		nextIdx := 0
-		bm.forEachSetBit(func(idx int) bool {
+		bm.forEachSetBitReadonly(func(idx int) {
 			if idx >= i {
 				t.Fatalf("index must be smaller than %d", i)
 			}
@@ -40,7 +40,6 @@ func TestBitmap(t *testing.T) {
 				t.Fatalf("unexpected idx; got %d; want %d", idx, nextIdx)
 			}
 			nextIdx++
-			return true
 		})
 
 		if !bm.areAllBitsSet() {
@@ -66,12 +65,11 @@ func TestBitmap(t *testing.T) {
 		}
 
 		nextIdx = 1
-		bm.forEachSetBit(func(idx int) bool {
+		bm.forEachSetBitReadonly(func(idx int) {
 			if idx != nextIdx {
 				t.Fatalf("unexpected idx; got %d; want %d", idx, nextIdx)
 			}
 			nextIdx += 2
-			return true
 		})
 
 		// Clear all the bits
@@ -93,9 +91,8 @@ func TestBitmap(t *testing.T) {
 		}
 
 		bitsCount := 0
-		bm.forEachSetBit(func(_ int) bool {
+		bm.forEachSetBitReadonly(func(_ int) {
 			bitsCount++
-			return true
 		})
 		if bitsCount != 0 {
 			t.Fatalf("unexpected non-zero number of set bits remained: %d", bitsCount)

lib/logstorage/bitmap_timing_test.go

@@ -4,6 +4,35 @@ import (
 	"testing"
 )
 
+func BenchmarkBitmapForEachSetBitReadonly(b *testing.B) {
+	const bitsLen = 64*1024
+
+	b.Run("no-zero-bits", func(b *testing.B) {
+		bm := getBitmap(bitsLen)
+		bm.setBits()
+		benchmarkBitmapForEachSetBitReadonly(b, bm)
+		putBitmap(bm)
+	})
+	b.Run("half-zero-bits", func(b *testing.B) {
+		bm := getBitmap(bitsLen)
+		bm.setBits()
+		bm.forEachSetBit(func(idx int) bool {
+			return idx%2 == 0
+		})
+		benchmarkBitmapForEachSetBitReadonly(b, bm)
+		putBitmap(bm)
+	})
+	b.Run("one-set-bit", func(b *testing.B) {
+		bm := getBitmap(bitsLen)
+		bm.setBits()
+		bm.forEachSetBit(func(idx int) bool {
+			return idx == bitsLen/2
+		})
+		benchmarkBitmapForEachSetBitReadonly(b, bm)
+		putBitmap(bm)
+	})
+}
+
 func BenchmarkBitmapForEachSetBit(b *testing.B) {
 	const bitsLen = 64*1024
 
@@ -57,14 +86,33 @@ func BenchmarkBitmapForEachSetBit(b *testing.B) {
 	})
 }
 
+func benchmarkBitmapForEachSetBitReadonly(b *testing.B, bm *bitmap) {
+	b.SetBytes(int64(bm.bitsLen))
+	b.ReportAllocs()
+	b.RunParallel(func(pb *testing.PB) {
+		bmLocal := getBitmap(bm.bitsLen)
+		n := 0
+		for pb.Next() {
+			bmLocal.copyFrom(bm)
+			bmLocal.forEachSetBitReadonly(func(idx int) {
+				n++
+			})
+		}
+		putBitmap(bmLocal)
+		GlobalSink.Add(uint64(n))
+	})
+}
+
 func benchmarkBitmapForEachSetBit(b *testing.B, bm *bitmap, isClearBits bool) {
 	b.SetBytes(int64(bm.bitsLen))
 	b.ReportAllocs()
 	b.RunParallel(func(pb *testing.PB) {
 		bmLocal := getBitmap(bm.bitsLen)
+		n := 0
 		for pb.Next() {
 			bmLocal.copyFrom(bm)
 			bmLocal.forEachSetBit(func(idx int) bool {
+				n++
 				return !isClearBits
 			})
 			if isClearBits {
@@ -78,5 +126,6 @@ func benchmarkBitmapForEachSetBit(b *testing.B, bm *bitmap, isClearBits bool) {
 			}
 		}
 		putBitmap(bmLocal)
+		GlobalSink.Add(uint64(n))
 	})
 }

lib/logstorage/block_result.go

@@ -278,10 +278,9 @@ func (br *blockResult) mustInit(bs *blockSearch, bm *bitmap) {
 
 	// Slow path - copy only the needed timestamps to br according to filter results.
 	dstTimestamps := br.timestamps[:0]
-	bm.forEachSetBit(func(idx int) bool {
+	bm.forEachSetBitReadonly(func(idx int) {
 		ts := srcTimestamps[idx]
 		dstTimestamps = append(dstTimestamps, ts)
-		return true
 	})
 	br.timestamps = dstTimestamps
 }