Initial commit: Go 1.23 release state

src/runtime/map_benchmark_test.go

@@ -0,0 +1,540 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+const size = 10
+
+func BenchmarkHashStringSpeed(b *testing.B) {
+	strings := make([]string, size)
+	for i := 0; i < size; i++ {
+		strings[i] = fmt.Sprintf("string#%d", i)
+	}
+	sum := 0
+	m := make(map[string]int, size)
+	for i := 0; i < size; i++ {
+		m[strings[i]] = 0
+	}
+	idx := 0
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		sum += m[strings[idx]]
+		idx++
+		if idx == size {
+			idx = 0
+		}
+	}
+}
+
+type chunk [17]byte
+
+func BenchmarkHashBytesSpeed(b *testing.B) {
+	// a bunch of chunks, each with a different alignment mod 16
+	var chunks [size]chunk
+	// initialize each to a different value
+	for i := 0; i < size; i++ {
+		chunks[i][0] = byte(i)
+	}
+	// put into a map
+	m := make(map[chunk]int, size)
+	for i, c := range chunks {
+		m[c] = i
+	}
+	idx := 0
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if m[chunks[idx]] != idx {
+			b.Error("bad map entry for chunk")
+		}
+		idx++
+		if idx == size {
+			idx = 0
+		}
+	}
+}
+
+func BenchmarkHashInt32Speed(b *testing.B) {
+	ints := make([]int32, size)
+	for i := 0; i < size; i++ {
+		ints[i] = int32(i)
+	}
+	sum := 0
+	m := make(map[int32]int, size)
+	for i := 0; i < size; i++ {
+		m[ints[i]] = 0
+	}
+	idx := 0
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		sum += m[ints[idx]]
+		idx++
+		if idx == size {
+			idx = 0
+		}
+	}
+}
+
+func BenchmarkHashInt64Speed(b *testing.B) {
+	ints := make([]int64, size)
+	for i := 0; i < size; i++ {
+		ints[i] = int64(i)
+	}
+	sum := 0
+	m := make(map[int64]int, size)
+	for i := 0; i < size; i++ {
+		m[ints[i]] = 0
+	}
+	idx := 0
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		sum += m[ints[idx]]
+		idx++
+		if idx == size {
+			idx = 0
+		}
+	}
+}
+func BenchmarkHashStringArraySpeed(b *testing.B) {
+	stringpairs := make([][2]string, size)
+	for i := 0; i < size; i++ {
+		for j := 0; j < 2; j++ {
+			stringpairs[i][j] = fmt.Sprintf("string#%d/%d", i, j)
+		}
+	}
+	sum := 0
+	m := make(map[[2]string]int, size)
+	for i := 0; i < size; i++ {
+		m[stringpairs[i]] = 0
+	}
+	idx := 0
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		sum += m[stringpairs[idx]]
+		idx++
+		if idx == size {
+			idx = 0
+		}
+	}
+}
+
+func BenchmarkMegMap(b *testing.B) {
+	m := make(map[string]bool)
+	for suffix := 'A'; suffix <= 'G'; suffix++ {
+		m[strings.Repeat("X", 1<<20-1)+fmt.Sprint(suffix)] = true
+	}
+	key := strings.Repeat("X", 1<<20-1) + "k"
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key]
+	}
+}
+
+func BenchmarkMegOneMap(b *testing.B) {
+	m := make(map[string]bool)
+	m[strings.Repeat("X", 1<<20)] = true
+	key := strings.Repeat("Y", 1<<20)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key]
+	}
+}
+
+func BenchmarkMegEqMap(b *testing.B) {
+	m := make(map[string]bool)
+	key1 := strings.Repeat("X", 1<<20)
+	key2 := strings.Repeat("X", 1<<20) // equal but different instance
+	m[key1] = true
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key2]
+	}
+}
+
+func BenchmarkMegEmptyMap(b *testing.B) {
+	m := make(map[string]bool)
+	key := strings.Repeat("X", 1<<20)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key]
+	}
+}
+
+func BenchmarkMegEmptyMapWithInterfaceKey(b *testing.B) {
+	m := make(map[any]bool)
+	key := strings.Repeat("X", 1<<20)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key]
+	}
+}
+
+func BenchmarkSmallStrMap(b *testing.B) {
+	m := make(map[string]bool)
+	for suffix := 'A'; suffix <= 'G'; suffix++ {
+		m[fmt.Sprint(suffix)] = true
+	}
+	key := "k"
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[key]
+	}
+}
+
+func BenchmarkMapStringKeysEight_16(b *testing.B) { benchmarkMapStringKeysEight(b, 16) }
+func BenchmarkMapStringKeysEight_32(b *testing.B) { benchmarkMapStringKeysEight(b, 32) }
+func BenchmarkMapStringKeysEight_64(b *testing.B) { benchmarkMapStringKeysEight(b, 64) }
+func BenchmarkMapStringKeysEight_1M(b *testing.B) { benchmarkMapStringKeysEight(b, 1<<20) }
+
+func benchmarkMapStringKeysEight(b *testing.B, keySize int) {
+	m := make(map[string]bool)
+	for i := 0; i < 8; i++ {
+		m[strings.Repeat("K", i+1)] = true
+	}
+	key := strings.Repeat("K", keySize)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = m[key]
+	}
+}
+
+func BenchmarkIntMap(b *testing.B) {
+	m := make(map[int]bool)
+	for i := 0; i < 8; i++ {
+		m[i] = true
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = m[7]
+	}
+}
+
+func BenchmarkMapFirst(b *testing.B) {
+	for n := 1; n <= 16; n++ {
+		b.Run(fmt.Sprintf("%d", n), func(b *testing.B) {
+			m := make(map[int]bool)
+			for i := 0; i < n; i++ {
+				m[i] = true
+			}
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				_ = m[0]
+			}
+		})
+	}
+}
+func BenchmarkMapMid(b *testing.B) {
+	for n := 1; n <= 16; n++ {
+		b.Run(fmt.Sprintf("%d", n), func(b *testing.B) {
+			m := make(map[int]bool)
+			for i := 0; i < n; i++ {
+				m[i] = true
+			}
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				_ = m[n>>1]
+			}
+		})
+	}
+}
+func BenchmarkMapLast(b *testing.B) {
+	for n := 1; n <= 16; n++ {
+		b.Run(fmt.Sprintf("%d", n), func(b *testing.B) {
+			m := make(map[int]bool)
+			for i := 0; i < n; i++ {
+				m[i] = true
+			}
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				_ = m[n-1]
+			}
+		})
+	}
+}
+
+func BenchmarkMapCycle(b *testing.B) {
+	// Arrange map entries to be a permutation, so that
+	// we hit all entries, and one lookup is data dependent
+	// on the previous lookup.
+	const N = 3127
+	p := rand.New(rand.NewSource(1)).Perm(N)
+	m := map[int]int{}
+	for i := 0; i < N; i++ {
+		m[i] = p[i]
+	}
+	b.ResetTimer()
+	j := 0
+	for i := 0; i < b.N; i++ {
+		j = m[j]
+	}
+	sink = uint64(j)
+}
+
+// Accessing the same keys in a row.
+func benchmarkRepeatedLookup(b *testing.B, lookupKeySize int) {
+	m := make(map[string]bool)
+	// At least bigger than a single bucket:
+	for i := 0; i < 64; i++ {
+		m[fmt.Sprintf("some key %d", i)] = true
+	}
+	base := strings.Repeat("x", lookupKeySize-1)
+	key1 := base + "1"
+	key2 := base + "2"
+	b.ResetTimer()
+	for i := 0; i < b.N/4; i++ {
+		_ = m[key1]
+		_ = m[key1]
+		_ = m[key2]
+		_ = m[key2]
+	}
+}
+
+func BenchmarkRepeatedLookupStrMapKey32(b *testing.B) { benchmarkRepeatedLookup(b, 32) }
+func BenchmarkRepeatedLookupStrMapKey1M(b *testing.B) { benchmarkRepeatedLookup(b, 1<<20) }
+
+func BenchmarkMakeMap(b *testing.B) {
+	b.Run("[Byte]Byte", func(b *testing.B) {
+		var m map[byte]byte
+		for i := 0; i < b.N; i++ {
+			m = make(map[byte]byte, 10)
+		}
+		hugeSink = m
+	})
+	b.Run("[Int]Int", func(b *testing.B) {
+		var m map[int]int
+		for i := 0; i < b.N; i++ {
+			m = make(map[int]int, 10)
+		}
+		hugeSink = m
+	})
+}
+
+func BenchmarkNewEmptyMap(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_ = make(map[int]int)
+	}
+}
+
+func BenchmarkNewSmallMap(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		m := make(map[int]int)
+		m[0] = 0
+		m[1] = 1
+	}
+}
+
+func BenchmarkMapIter(b *testing.B) {
+	m := make(map[int]bool)
+	for i := 0; i < 8; i++ {
+		m[i] = true
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		for range m {
+		}
+	}
+}
+
+func BenchmarkMapIterEmpty(b *testing.B) {
+	m := make(map[int]bool)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		for range m {
+		}
+	}
+}
+
+func BenchmarkSameLengthMap(b *testing.B) {
+	// long strings, same length, differ in first few
+	// and last few bytes.
+	m := make(map[string]bool)
+	s1 := "foo" + strings.Repeat("-", 100) + "bar"
+	s2 := "goo" + strings.Repeat("-", 100) + "ber"
+	m[s1] = true
+	m[s2] = true
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = m[s1]
+	}
+}
+
+type BigKey [3]int64
+
+func BenchmarkBigKeyMap(b *testing.B) {
+	m := make(map[BigKey]bool)
+	k := BigKey{3, 4, 5}
+	m[k] = true
+	for i := 0; i < b.N; i++ {
+		_ = m[k]
+	}
+}
+
+type BigVal [3]int64
+
+func BenchmarkBigValMap(b *testing.B) {
+	m := make(map[BigKey]BigVal)
+	k := BigKey{3, 4, 5}
+	m[k] = BigVal{6, 7, 8}
+	for i := 0; i < b.N; i++ {
+		_ = m[k]
+	}
+}
+
+func BenchmarkSmallKeyMap(b *testing.B) {
+	m := make(map[int16]bool)
+	m[5] = true
+	for i := 0; i < b.N; i++ {
+		_ = m[5]
+	}
+}
+
+func BenchmarkMapPopulate(b *testing.B) {
+	for size := 1; size < 1000000; size *= 10 {
+		b.Run(strconv.Itoa(size), func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				m := make(map[int]bool)
+				for j := 0; j < size; j++ {
+					m[j] = true
+				}
+			}
+		})
+	}
+}
+
+type ComplexAlgKey struct {
+	a, b, c int64
+	_       int
+	d       int32
+	_       int
+	e       string
+	_       int
+	f, g, h int64
+}
+
+func BenchmarkComplexAlgMap(b *testing.B) {
+	m := make(map[ComplexAlgKey]bool)
+	var k ComplexAlgKey
+	m[k] = true
+	for i := 0; i < b.N; i++ {
+		_ = m[k]
+	}
+}
+
+func BenchmarkGoMapClear(b *testing.B) {
+	b.Run("Reflexive", func(b *testing.B) {
+		for size := 1; size < 100000; size *= 10 {
+			b.Run(strconv.Itoa(size), func(b *testing.B) {
+				m := make(map[int]int, size)
+				for i := 0; i < b.N; i++ {
+					m[0] = size // Add one element so len(m) != 0 avoiding fast paths.
+					clear(m)
+				}
+			})
+		}
+	})
+	b.Run("NonReflexive", func(b *testing.B) {
+		for size := 1; size < 100000; size *= 10 {
+			b.Run(strconv.Itoa(size), func(b *testing.B) {
+				m := make(map[float64]int, size)
+				for i := 0; i < b.N; i++ {
+					m[1.0] = size // Add one element so len(m) != 0 avoiding fast paths.
+					clear(m)
+				}
+			})
+		}
+	})
+}
+
+func BenchmarkMapStringConversion(b *testing.B) {
+	for _, length := range []int{32, 64} {
+		b.Run(strconv.Itoa(length), func(b *testing.B) {
+			bytes := make([]byte, length)
+			b.Run("simple", func(b *testing.B) {
+				b.ReportAllocs()
+				m := make(map[string]int)
+				m[string(bytes)] = 0
+				for i := 0; i < b.N; i++ {
+					_ = m[string(bytes)]
+				}
+			})
+			b.Run("struct", func(b *testing.B) {
+				b.ReportAllocs()
+				type stringstruct struct{ s string }
+				m := make(map[stringstruct]int)
+				m[stringstruct{string(bytes)}] = 0
+				for i := 0; i < b.N; i++ {
+					_ = m[stringstruct{string(bytes)}]
+				}
+			})
+			b.Run("array", func(b *testing.B) {
+				b.ReportAllocs()
+				type stringarray [1]string
+				m := make(map[stringarray]int)
+				m[stringarray{string(bytes)}] = 0
+				for i := 0; i < b.N; i++ {
+					_ = m[stringarray{string(bytes)}]
+				}
+			})
+		})
+	}
+}
+
+var BoolSink bool
+
+func BenchmarkMapInterfaceString(b *testing.B) {
+	m := map[any]bool{}
+
+	for i := 0; i < 100; i++ {
+		m[fmt.Sprintf("%d", i)] = true
+	}
+
+	key := (any)("A")
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		BoolSink = m[key]
+	}
+}
+func BenchmarkMapInterfacePtr(b *testing.B) {
+	m := map[any]bool{}
+
+	for i := 0; i < 100; i++ {
+		i := i
+		m[&i] = true
+	}
+
+	key := new(int)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		BoolSink = m[key]
+	}
+}
+
+var (
+	hintLessThan8    = 7
+	hintGreaterThan8 = 32
+)
+
+func BenchmarkNewEmptyMapHintLessThan8(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_ = make(map[int]int, hintLessThan8)
+	}
+}
+
+func BenchmarkNewEmptyMapHintGreaterThan8(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_ = make(map[int]int, hintGreaterThan8)
+	}
+}