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benchmark more readable bit twiddler
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@gaissmai
gaissmai committed Dec 13, 2024
1 parent 8812901 commit 5619907
Showing 1 changed file with 67 additions and 44 deletions.
111 changes: 67 additions & 44 deletions bitset_benchmark_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -283,7 +283,7 @@ func BenchmarkLemireIterateManyb(b *testing.B) {
}

func setRnd(bits []uint64, halfings int) {
var rnd = rand.NewSource(0).(rand.Source64)
rnd := rand.NewSource(0).(rand.Source64)
for i := range bits {
bits[i] = 0xFFFFFFFFFFFFFFFF
for j := 0; j < halfings; j++ {
Expand All @@ -294,14 +294,14 @@ func setRnd(bits []uint64, halfings int) {

// go test -bench=BenchmarkFlorianUekermannIterateMany
func BenchmarkFlorianUekermannIterateMany(b *testing.B) {
var input = make([]uint64, 68)
input := make([]uint64, 68)
setRnd(input, 4)
var bitmap = From(input)
bitmap := From(input)
buffer := make([]uint, 256)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
var last, batch = bitmap.NextSetMany(0, buffer)
last, batch := bitmap.NextSetMany(0, buffer)
for len(batch) > 0 {
for _, idx := range batch {
checksum += idx
Expand All @@ -315,11 +315,11 @@ func BenchmarkFlorianUekermannIterateMany(b *testing.B) {
}

func BenchmarkFlorianUekermannIterateManyReg(b *testing.B) {
var input = make([]uint64, 68)
input := make([]uint64, 68)
setRnd(input, 4)
var bitmap = From(input)
bitmap := From(input)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
for j, e := bitmap.NextSet(0); e; j, e = bitmap.NextSet(j + 1) {
checksum += j
Expand All @@ -333,22 +333,22 @@ func BenchmarkFlorianUekermannIterateManyReg(b *testing.B) {
// function provided by FlorianUekermann
func good(set []uint64) (checksum uint) {
for wordIdx, word := range set {
var wordIdx = uint(wordIdx * 64)
wordIdx := uint(wordIdx * 64)
for word != 0 {
var bitIdx = uint(bits.TrailingZeros64(word))
bitIdx := uint(bits.TrailingZeros64(word))
word ^= 1 << bitIdx
var index = wordIdx + bitIdx
index := wordIdx + bitIdx
checksum += index
}
}
return checksum
}

func BenchmarkFlorianUekermannIterateManyComp(b *testing.B) {
var input = make([]uint64, 68)
input := make([]uint64, 68)
setRnd(input, 4)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
checksum += good(input)
}
Expand All @@ -361,15 +361,15 @@ func BenchmarkFlorianUekermannIterateManyComp(b *testing.B) {

// go test -bench=BenchmarkFlorianUekermannLowDensityIterateMany
func BenchmarkFlorianUekermannLowDensityIterateMany(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 50000; i++ {
input[rnd.Uint64()%1000000] = 1
}
var bitmap = From(input)
bitmap := From(input)
buffer := make([]uint, 256)
b.ResetTimer()
var sum = uint(0)
sum := uint(0)
for i := 0; i < b.N; i++ {
j := uint(0)
j, buffer = bitmap.NextSetMany(j, buffer)
Expand All @@ -386,14 +386,14 @@ func BenchmarkFlorianUekermannLowDensityIterateMany(b *testing.B) {
}

func BenchmarkFlorianUekermannLowDensityIterateManyReg(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 50000; i++ {
input[rnd.Uint64()%1000000] = 1
}
var bitmap = From(input)
bitmap := From(input)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
for j, e := bitmap.NextSet(0); e; j, e = bitmap.NextSet(j + 1) {
checksum += j
Expand All @@ -405,13 +405,13 @@ func BenchmarkFlorianUekermannLowDensityIterateManyReg(b *testing.B) {
}

func BenchmarkFlorianUekermannLowDensityIterateManyComp(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 50000; i++ {
input[rnd.Uint64()%1000000] = 1
}
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
checksum += good(input)
}
Expand All @@ -424,12 +424,12 @@ func BenchmarkFlorianUekermannLowDensityIterateManyComp(b *testing.B) {

// go test -bench=BenchmarkFlorianUekermannMidDensityIterateMany
func BenchmarkFlorianUekermannMidDensityIterateMany(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 3000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
var bitmap = From(input)
bitmap := From(input)
buffer := make([]uint, 256)
b.ResetTimer()
sum := uint(0)
Expand All @@ -450,14 +450,14 @@ func BenchmarkFlorianUekermannMidDensityIterateMany(b *testing.B) {
}

func BenchmarkFlorianUekermannMidDensityIterateManyReg(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 3000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
var bitmap = From(input)
bitmap := From(input)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
for j, e := bitmap.NextSet(0); e; j, e = bitmap.NextSet(j + 1) {
checksum += j
Expand All @@ -469,13 +469,13 @@ func BenchmarkFlorianUekermannMidDensityIterateManyReg(b *testing.B) {
}

func BenchmarkFlorianUekermannMidDensityIterateManyComp(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 3000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
checksum += good(input)
}
Expand All @@ -487,12 +487,12 @@ func BenchmarkFlorianUekermannMidDensityIterateManyComp(b *testing.B) {
////////// High density

func BenchmarkFlorianUekermannMidStrongDensityIterateMany(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 20000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
var bitmap = From(input)
bitmap := From(input)
buffer := make([]uint, 256)
b.ResetTimer()
sum := uint(0)
Expand All @@ -513,14 +513,14 @@ func BenchmarkFlorianUekermannMidStrongDensityIterateMany(b *testing.B) {
}

func BenchmarkFlorianUekermannMidStrongDensityIterateManyReg(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 20000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
var bitmap = From(input)
bitmap := From(input)
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
for j, e := bitmap.NextSet(0); e; j, e = bitmap.NextSet(j + 1) {
checksum += j
Expand All @@ -532,13 +532,13 @@ func BenchmarkFlorianUekermannMidStrongDensityIterateManyReg(b *testing.B) {
}

func BenchmarkFlorianUekermannMidStrongDensityIterateManyComp(b *testing.B) {
var input = make([]uint64, 1000000)
var rnd = rand.NewSource(0).(rand.Source64)
input := make([]uint64, 1000000)
rnd := rand.NewSource(0).(rand.Source64)
for i := 0; i < 20000000; i++ {
input[rnd.Uint64()%1000000] |= uint64(1) << (rnd.Uint64() % 64)
}
b.ResetTimer()
var checksum = uint(0)
checksum := uint(0)
for i := 0; i < b.N; i++ {
checksum += good(input)
}
Expand Down Expand Up @@ -635,3 +635,26 @@ func BenchmarkIsSuperSet(b *testing.B) {
len, len, density, overrideS, overrideSS, fStrict)
}
}

// clear the right most bit (C-RMS)
// test two different algorithms
func BenchmarkClearRMS(b *testing.B) {
var word uint64

// cryptic
b.Run("cryptic", func(b *testing.B) {
word = 0xaaaa_aaaa_aaaa_aaaa
for i := 0; i < b.N; i++ {
t := word & ((^word) + 1)
word = word ^ t
}
})

// less cryptic
b.Run("simple", func(b *testing.B) {
word = 0xaaaa_aaaa_aaaa_aaaa
for i := 0; i < b.N; i++ {
word &= word - 1
}
})
}

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