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lib/uint64set: reduce the size of bucket16 by storing smallPool by pointer.

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This reduces CPU time spent on bucket16 copying inside bucket13.addBucketAtPos.
This commit is contained in:
Aliaksandr Valialkin 2021-03-15 17:23:29 +02:00
parent eb103e1527
commit fb82c4b9fa
1 changed files with 46 additions and 11 deletions
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57
lib/uint64set/uint64set.go
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@ -729,8 +729,8 @@ const (
type bucket16 struct {
bits *[wordsPerBucket]uint64
smallPool *[smallPoolSize]uint16
smallPoolLen int
smallPool [smallPoolSize]uint16
}
const smallPoolSize = 56
@ -807,7 +807,14 @@ func (b *bucket16) intersect(a *bucket16) {
}
func (b *bucket16) sizeBytes() uint64 {
return uint64(unsafe.Sizeof(*b)) + uint64(unsafe.Sizeof(*b.bits))
n := unsafe.Sizeof(*b)
if b.bits != nil {
n += unsafe.Sizeof(*b.bits)
}
if b.smallPool != nil {
n += unsafe.Sizeof(*b.smallPool)
}
return uint64(n)
}
func (b *bucket16) copyTo(dst *bucket16) {
@ -818,7 +825,18 @@ func (b *bucket16) copyTo(dst *bucket16) {
dst.bits = &bits
}
dst.smallPoolLen = b.smallPoolLen
dst.smallPool = b.smallPool
if b.smallPool != nil {
sp := dst.getOrCreateSmallPool()
*sp = *b.smallPool
}
}
func (b *bucket16) getOrCreateSmallPool() *[smallPoolSize]uint16 {
if b.smallPool == nil {
var sp [smallPoolSize]uint16
b.smallPool = &sp
}
return b.smallPool
}
func (b *bucket16) add(x uint16) bool {
@ -861,15 +879,16 @@ func (b *bucket16) addToSmallPool(x uint16) bool {
if b.hasInSmallPool(x) {
return false
}
if b.smallPoolLen < len(b.smallPool) {
b.smallPool[b.smallPoolLen] = x
sp := b.getOrCreateSmallPool()
if b.smallPoolLen < len(sp) {
sp[b.smallPoolLen] = x
b.smallPoolLen++
return true
}
b.smallPoolLen = 0
var bits [wordsPerBucket]uint64
b.bits = &bits
for _, v := range b.smallPool[:] {
for _, v := range sp[:] {
b.add(v)
}
b.add(x)
@ -885,7 +904,11 @@ func (b *bucket16) has(x uint16) bool {
}
func (b *bucket16) hasInSmallPool(x uint16) bool {
for _, v := range b.smallPool[:b.smallPoolLen] {
sp := b.smallPool
if sp == nil {
return false
}
for _, v := range sp[:b.smallPoolLen] {
if v == x {
return true
}
@ -905,9 +928,13 @@ func (b *bucket16) del(x uint16) bool {
}
func (b *bucket16) delFromSmallPool(x uint16) bool {
for i, v := range b.smallPool[:b.smallPoolLen] {
sp := b.smallPool
if sp == nil {
return false
}
for i, v := range sp[:b.smallPoolLen] {
if v == x {
copy(b.smallPool[i:], b.smallPool[i+1:])
copy(sp[i:], sp[i+1:])
b.smallPoolLen--
return true
}
@ -918,11 +945,15 @@ func (b *bucket16) delFromSmallPool(x uint16) bool {
func (b *bucket16) appendTo(dst []uint64, hi uint32, hi16 uint16) []uint64 {
hi64 := uint64(hi)<<32 | uint64(hi16)<<16
if b.bits == nil {
sp := b.smallPool
if sp == nil {
return dst
}
// Use smallPoolSorter instead of sort.Slice here in order to reduce memory allocations.
sps := smallPoolSorterPool.Get().(*smallPoolSorter)
// Sort a copy of b.smallPool, since b must be readonly in order to prevent from data races
// Sort a copy of sp, since b must be readonly in order to prevent from data races
// when b.appendTo is called from concurrent goroutines.
sps.smallPool = b.smallPool
sps.smallPool = *sp
sps.a = sps.smallPool[:b.smallPoolLen]
if len(sps.a) > 1 && !sort.IsSorted(sps) {
sort.Sort(sps)
@ -985,6 +1016,10 @@ func getWordNumBitMask(x uint16) (uint16, uint64) {
func binarySearch16(u16 []uint16, x uint16) int {
// The code has been adapted from sort.Search.
n := len(u16)
if n > 0 && u16[n-1] < x {
// Fast path for values scanned in ascending order.
return n
}
i, j := 0, n
for i < j {
h := int(uint(i+j) >> 1)