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path: root/src/runtime/map_test.go
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Diffstat (limited to 'src/runtime/map_test.go')
-rw-r--r--src/runtime/map_test.go214
1 files changed, 190 insertions, 24 deletions
diff --git a/src/runtime/map_test.go b/src/runtime/map_test.go
index 81f05a0613..6ed655de0a 100644
--- a/src/runtime/map_test.go
+++ b/src/runtime/map_test.go
@@ -244,7 +244,7 @@ func testConcurrentReadsAfterGrowth(t *testing.T, useReflect bool) {
numGrowStep := 250
numReader := 16
if testing.Short() {
- numLoop, numGrowStep = 2, 500
+ numLoop, numGrowStep = 2, 100
}
for i := 0; i < numLoop; i++ {
m := make(map[int]int, 0)
@@ -596,6 +596,134 @@ func TestIgnoreBogusMapHint(t *testing.T) {
}
}
+var mapSink map[int]int
+
+var mapBucketTests = [...]struct {
+ n int // n is the number of map elements
+ noescape int // number of expected buckets for non-escaping map
+ escape int // number of expected buckets for escaping map
+}{
+ {-(1 << 30), 1, 1},
+ {-1, 1, 1},
+ {0, 1, 1},
+ {1, 1, 1},
+ {8, 1, 1},
+ {9, 2, 2},
+ {13, 2, 2},
+ {14, 4, 4},
+ {26, 4, 4},
+}
+
+func TestMapBuckets(t *testing.T) {
+ // Test that maps of different sizes have the right number of buckets.
+ // Non-escaping maps with small buckets (like map[int]int) never
+ // have a nil bucket pointer due to starting with preallocated buckets
+ // on the stack. Escaping maps start with a non-nil bucket pointer if
+ // hint size is above bucketCnt and thereby have more than one bucket.
+ // These tests depend on bucketCnt and loadFactor* in hashmap.go.
+ t.Run("mapliteral", func(t *testing.T) {
+ for _, tt := range mapBucketTests {
+ localMap := map[int]int{}
+ if runtime.MapBucketsPointerIsNil(localMap) {
+ t.Errorf("no escape: buckets pointer is nil for non-escaping map")
+ }
+ for i := 0; i < tt.n; i++ {
+ localMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(localMap); got != tt.noescape {
+ t.Errorf("no escape: n=%d want %d buckets, got %d", tt.n, tt.noescape, got)
+ }
+ escapingMap := map[int]int{}
+ if count := runtime.MapBucketsCount(escapingMap); count > 1 && runtime.MapBucketsPointerIsNil(escapingMap) {
+ t.Errorf("escape: buckets pointer is nil for n=%d buckets", count)
+ }
+ for i := 0; i < tt.n; i++ {
+ escapingMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(escapingMap); got != tt.escape {
+ t.Errorf("escape n=%d want %d buckets, got %d", tt.n, tt.escape, got)
+ }
+ mapSink = escapingMap
+ }
+ })
+ t.Run("nohint", func(t *testing.T) {
+ for _, tt := range mapBucketTests {
+ localMap := make(map[int]int)
+ if runtime.MapBucketsPointerIsNil(localMap) {
+ t.Errorf("no escape: buckets pointer is nil for non-escaping map")
+ }
+ for i := 0; i < tt.n; i++ {
+ localMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(localMap); got != tt.noescape {
+ t.Errorf("no escape: n=%d want %d buckets, got %d", tt.n, tt.noescape, got)
+ }
+ escapingMap := make(map[int]int)
+ if count := runtime.MapBucketsCount(escapingMap); count > 1 && runtime.MapBucketsPointerIsNil(escapingMap) {
+ t.Errorf("escape: buckets pointer is nil for n=%d buckets", count)
+ }
+ for i := 0; i < tt.n; i++ {
+ escapingMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(escapingMap); got != tt.escape {
+ t.Errorf("escape: n=%d want %d buckets, got %d", tt.n, tt.escape, got)
+ }
+ mapSink = escapingMap
+ }
+ })
+ t.Run("makemap", func(t *testing.T) {
+ for _, tt := range mapBucketTests {
+ localMap := make(map[int]int, tt.n)
+ if runtime.MapBucketsPointerIsNil(localMap) {
+ t.Errorf("no escape: buckets pointer is nil for non-escaping map")
+ }
+ for i := 0; i < tt.n; i++ {
+ localMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(localMap); got != tt.noescape {
+ t.Errorf("no escape: n=%d want %d buckets, got %d", tt.n, tt.noescape, got)
+ }
+ escapingMap := make(map[int]int, tt.n)
+ if count := runtime.MapBucketsCount(escapingMap); count > 1 && runtime.MapBucketsPointerIsNil(escapingMap) {
+ t.Errorf("escape: buckets pointer is nil for n=%d buckets", count)
+ }
+ for i := 0; i < tt.n; i++ {
+ escapingMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(escapingMap); got != tt.escape {
+ t.Errorf("escape: n=%d want %d buckets, got %d", tt.n, tt.escape, got)
+ }
+ mapSink = escapingMap
+ }
+ })
+ t.Run("makemap64", func(t *testing.T) {
+ for _, tt := range mapBucketTests {
+ localMap := make(map[int]int, int64(tt.n))
+ if runtime.MapBucketsPointerIsNil(localMap) {
+ t.Errorf("no escape: buckets pointer is nil for non-escaping map")
+ }
+ for i := 0; i < tt.n; i++ {
+ localMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(localMap); got != tt.noescape {
+ t.Errorf("no escape: n=%d want %d buckets, got %d", tt.n, tt.noescape, got)
+ }
+ escapingMap := make(map[int]int, tt.n)
+ if count := runtime.MapBucketsCount(escapingMap); count > 1 && runtime.MapBucketsPointerIsNil(escapingMap) {
+ t.Errorf("escape: buckets pointer is nil for n=%d buckets", count)
+ }
+ for i := 0; i < tt.n; i++ {
+ escapingMap[i] = i
+ }
+ if got := runtime.MapBucketsCount(escapingMap); got != tt.escape {
+ t.Errorf("escape: n=%d want %d buckets, got %d", tt.n, tt.escape, got)
+ }
+ mapSink = escapingMap
+ }
+ })
+
+}
+
func benchmarkMapPop(b *testing.B, n int) {
m := map[int]int{}
for i := 0; i < b.N; i++ {
@@ -617,14 +745,38 @@ func BenchmarkMapPop100(b *testing.B) { benchmarkMapPop(b, 100) }
func BenchmarkMapPop1000(b *testing.B) { benchmarkMapPop(b, 1000) }
func BenchmarkMapPop10000(b *testing.B) { benchmarkMapPop(b, 10000) }
+var testNonEscapingMapVariable int = 8
+
func TestNonEscapingMap(t *testing.T) {
n := testing.AllocsPerRun(1000, func() {
+ m := map[int]int{}
+ m[0] = 0
+ })
+ if n != 0 {
+ t.Fatalf("mapliteral: want 0 allocs, got %v", n)
+ }
+ n = testing.AllocsPerRun(1000, func() {
m := make(map[int]int)
m[0] = 0
})
if n != 0 {
- t.Fatalf("want 0 allocs, got %v", n)
+ t.Fatalf("no hint: want 0 allocs, got %v", n)
+ }
+ n = testing.AllocsPerRun(1000, func() {
+ m := make(map[int]int, 8)
+ m[0] = 0
+ })
+ if n != 0 {
+ t.Fatalf("with small hint: want 0 allocs, got %v", n)
+ }
+ n = testing.AllocsPerRun(1000, func() {
+ m := make(map[int]int, testNonEscapingMapVariable)
+ m[0] = 0
+ })
+ if n != 0 {
+ t.Fatalf("with variable hint: want 0 allocs, got %v", n)
}
+
}
func benchmarkMapAssignInt32(b *testing.B, n int) {
@@ -635,12 +787,16 @@ func benchmarkMapAssignInt32(b *testing.B, n int) {
}
func benchmarkMapDeleteInt32(b *testing.B, n int) {
- a := make(map[int32]int)
- for i := 0; i < n*b.N; i++ {
- a[int32(i)] = i
- }
+ a := make(map[int32]int, n)
b.ResetTimer()
- for i := 0; i < n*b.N; i = i + n {
+ for i := 0; i < b.N; i++ {
+ if len(a) == 0 {
+ b.StopTimer()
+ for j := i; j < i+n; j++ {
+ a[int32(j)] = j
+ }
+ b.StartTimer()
+ }
delete(a, int32(i))
}
}
@@ -653,12 +809,16 @@ func benchmarkMapAssignInt64(b *testing.B, n int) {
}
func benchmarkMapDeleteInt64(b *testing.B, n int) {
- a := make(map[int64]int)
- for i := 0; i < n*b.N; i++ {
- a[int64(i)] = i
- }
+ a := make(map[int64]int, n)
b.ResetTimer()
- for i := 0; i < n*b.N; i = i + n {
+ for i := 0; i < b.N; i++ {
+ if len(a) == 0 {
+ b.StopTimer()
+ for j := i; j < i+n; j++ {
+ a[int64(j)] = j
+ }
+ b.StartTimer()
+ }
delete(a, int64(i))
}
}
@@ -676,17 +836,23 @@ func benchmarkMapAssignStr(b *testing.B, n int) {
}
func benchmarkMapDeleteStr(b *testing.B, n int) {
- k := make([]string, n*b.N)
- for i := 0; i < n*b.N; i++ {
- k[i] = strconv.Itoa(i)
- }
- a := make(map[string]int)
- for i := 0; i < n*b.N; i++ {
- a[k[i]] = i
+ i2s := make([]string, n)
+ for i := 0; i < n; i++ {
+ i2s[i] = strconv.Itoa(i)
}
+ a := make(map[string]int, n)
b.ResetTimer()
- for i := 0; i < n*b.N; i = i + n {
- delete(a, k[i])
+ k := 0
+ for i := 0; i < b.N; i++ {
+ if len(a) == 0 {
+ b.StopTimer()
+ for j := 0; j < n; j++ {
+ a[i2s[j]] = j
+ }
+ k = i
+ b.StartTimer()
+ }
+ delete(a, i2s[i-k])
}
}
@@ -705,7 +871,7 @@ func BenchmarkMapAssign(b *testing.B) {
}
func BenchmarkMapDelete(b *testing.B) {
- b.Run("Int32", runWith(benchmarkMapDeleteInt32, 1, 2, 4))
- b.Run("Int64", runWith(benchmarkMapDeleteInt64, 1, 2, 4))
- b.Run("Str", runWith(benchmarkMapDeleteStr, 1, 2, 4))
+ b.Run("Int32", runWith(benchmarkMapDeleteInt32, 100, 1000, 10000))
+ b.Run("Int64", runWith(benchmarkMapDeleteInt64, 100, 1000, 10000))
+ b.Run("Str", runWith(benchmarkMapDeleteStr, 100, 1000, 10000))
}
generated by cgit v1.3-5-g9baa (git 2.53.0) at 2026-04-17 16:23:14 +0000