seaweedfs/go/util/bytes_pool.go
chrislusf 0649d778a7 pooling []byte
reduce the number of requests to make([]byte)
2016-04-14 01:30:26 -07:00

128 lines
2.5 KiB
Go

package util
import (
"bytes"
"fmt"
"sync"
"sync/atomic"
"time"
)
var (
ChunkSizes = []int{
1 << 4, // index 0, 16 bytes, inclusive
1 << 6, // index 1, 64 bytes
1 << 8, // index 2, 256 bytes
1 << 10, // index 3, 1K bytes
1 << 12, // index 4, 4K bytes
1 << 14, // index 5, 16K bytes
1 << 16, // index 6, 64K bytes
1 << 18, // index 7, 256K bytes
1 << 20, // index 8, 1M bytes
1 << 22, // index 9, 4M bytes
1 << 24, // index 10, 16M bytes
1 << 26, // index 11, 64M bytes
1 << 28, // index 12, 128M bytes
}
_DEBUG = false
)
type BytesPool struct {
chunkPools []*byteChunkPool
}
func NewBytesPool() *BytesPool {
var bp BytesPool
for _, size := range ChunkSizes {
bp.chunkPools = append(bp.chunkPools, newByteChunkPool(size))
}
ret := &bp
if _DEBUG {
t := time.NewTicker(10 * time.Second)
go func() {
for {
println("buffer:", ret.String())
<-t.C
}
}()
}
return ret
}
func (m *BytesPool) String() string {
var buf bytes.Buffer
for index, size := range ChunkSizes {
if m.chunkPools[index].count > 0 {
buf.WriteString(fmt.Sprintf("size:%d count:%d\n", size, m.chunkPools[index].count))
}
}
return buf.String()
}
func findChunkPoolIndex(size int) int {
if size <= 0 {
return -1
}
size = (size - 1) >> 4
ret := 0
for size > 0 {
size = size >> 2
ret = ret + 1
}
if ret >= len(ChunkSizes) {
return -1
}
return ret
}
func (m *BytesPool) Get(size int) []byte {
index := findChunkPoolIndex(size)
// println("get index:", index)
if index < 0 {
return make([]byte, size)
}
return m.chunkPools[index].Get()
}
func (m *BytesPool) Put(b []byte) {
index := findChunkPoolIndex(len(b))
// println("put index:", index)
if index < 0 {
return
}
m.chunkPools[index].Put(b)
}
// a pool of fix-sized []byte chunks. The pool size is managed by Go GC
type byteChunkPool struct {
sync.Pool
chunkSizeLimit int
count int64
}
var count int
func newByteChunkPool(chunkSizeLimit int) *byteChunkPool {
var m byteChunkPool
m.chunkSizeLimit = chunkSizeLimit
m.Pool.New = func() interface{} {
count++
// println("creating []byte size", m.chunkSizeLimit, "new", count, "count", m.count)
return make([]byte, m.chunkSizeLimit)
}
return &m
}
func (m *byteChunkPool) Get() []byte {
// println("before get size:", m.chunkSizeLimit, "count:", m.count)
atomic.AddInt64(&m.count, 1)
return m.Pool.Get().([]byte)
}
func (m *byteChunkPool) Put(b []byte) {
atomic.AddInt64(&m.count, -1)
// println("after put get size:", m.chunkSizeLimit, "count:", m.count)
m.Pool.Put(b)
}