优化ringbuffer

utils/io2/ring.go

@@ -1,36 +1,49 @@
 package io2
 
 import (
-	"fmt"
 	"io"
 	"sync"
 	"time"
+
+	"gitlink.org.cn/cloudream/common/utils/math2"
 )
 
-type RingBuffer2 struct {
-	buf            []byte
-	src            io.ReadCloser
-	err            error
-	isReading      bool
-	writePos       int // 指向下一次写入的位置，应该是一个空位
-	readPos        int // 执行下一次读取的位置，应该是有效数据
-	waitReading    *sync.Cond
-	waitComsuming  *sync.Cond
-	UpstreamName   string
-	DownstreamName string
+type RingBufferStats struct {
+	MaxWaitDataTime        time.Duration // 外部读取数据时的最长等待时间
+	MaxWaitFreeSpaceTime   time.Duration // 从数据源读取数据之前，等待空闲空间的最长时间
+	TotalWaitDataTime      time.Duration // 总等待读取数据的时间
+	TotalWaitFreeSpaceTime time.Duration // 总等待空闲空间的时间
+}
+
+type RingBuffer struct {
+	buf           []byte
+	src           io.ReadCloser
+	maxPerRead    int // 后台读取线程每次读取的最大字节数，太小会导致IO次数增多，太大会导致读、写并行性下降
+	err           error
+	isReading     bool
+	writePos      int // 指向下一次写入的位置，应该是一个空位
+	readPos       int // 执行下一次读取的位置，应该是有效数据
+	waitReading   *sync.Cond
+	waitComsuming *sync.Cond
+	stats         RingBufferStats
 }
 
-func RingBuffer(src io.ReadCloser, size int) *RingBuffer2 {
+func Ring(src io.ReadCloser, size int) *RingBuffer {
 	lk := &sync.Mutex{}
-	return &RingBuffer2{
+	return &RingBuffer{
 		buf:           make([]byte, size),
 		src:           src,
+		maxPerRead:    size / 4,
 		waitReading:   sync.NewCond(lk),
 		waitComsuming: sync.NewCond(lk),
 	}
 }
 
-func (r *RingBuffer2) Read(p []byte) (n int, err error) {
+func (r *RingBuffer) Stats() RingBufferStats {
+	return r.stats
+}
+
+func (r *RingBuffer) Read(p []byte) (n int, err error) {
 	r.waitReading.L.Lock()
 	if !r.isReading {
 		go r.reading()
@@ -45,16 +58,20 @@ func (r *RingBuffer2) Read(p []byte) (n int, err error) {
 
 		startTime := time.Now()
 		r.waitReading.Wait()
-		fmt.Printf("%s wait data for %v\n", r.DownstreamName, time.Since(startTime))
+		dt := time.Since(startTime)
+		r.stats.MaxWaitDataTime = math2.Max(r.stats.MaxWaitDataTime, dt)
+		r.stats.TotalWaitDataTime += dt
 	}
 	writePos := r.writePos
 	readPos := r.readPos
 	r.waitReading.L.Unlock()
 
 	if readPos < writePos {
-		n = copy(p, r.buf[readPos:writePos])
+		maxRead := math2.Min(r.maxPerRead, writePos-readPos)
+		n = copy(p, r.buf[readPos:readPos+maxRead])
 	} else {
-		n = copy(p, r.buf[readPos:])
+		maxRead := math2.Min(r.maxPerRead, len(r.buf)-readPos)
+		n = copy(p, r.buf[readPos:readPos+maxRead])
 	}
 
 	r.waitComsuming.L.Lock()
@@ -66,7 +83,7 @@ func (r *RingBuffer2) Read(p []byte) (n int, err error) {
 	return
 }
 
-func (r *RingBuffer2) Close() error {
+func (r *RingBuffer) Close() error {
 	r.src.Close()
 	r.waitComsuming.L.Lock()
 	r.err = io.ErrClosedPipe
@@ -76,7 +93,7 @@ func (r *RingBuffer2) Close() error {
 	return nil
 }
 
-func (r *RingBuffer2) reading() {
+func (r *RingBuffer) reading() {
 	defer r.src.Close()
 
 	for {
@@ -86,7 +103,9 @@ func (r *RingBuffer2) reading() {
 		for (r.writePos+1)%len(r.buf) == r.readPos {
 			startTime := time.Now()
 			r.waitComsuming.Wait()
-			fmt.Printf("%s wait free space for %v\n", r.UpstreamName, time.Since(startTime))
+			dt := time.Since(startTime)
+			r.stats.MaxWaitFreeSpaceTime = math2.Max(r.stats.MaxWaitFreeSpaceTime, dt)
+			r.stats.TotalWaitFreeSpaceTime += dt
 
 			if r.err != nil {
 				return
@@ -102,12 +121,15 @@ func (r *RingBuffer2) reading() {
 			// 同上理，写入数据的时候如果readPos为0，则它的前一格是底层缓冲区的最后一格
 			// 那就不能写入到这一格
 			if readPos == 0 {
-				n, err = r.src.Read(r.buf[writePos : len(r.buf)-1])
+				maxWrite := math2.Min(r.maxPerRead, len(r.buf)-1-writePos)
+				n, err = r.src.Read(r.buf[writePos : writePos+maxWrite])
 			} else {
-				n, err = r.src.Read(r.buf[writePos:])
+				maxWrite := math2.Min(r.maxPerRead, len(r.buf)-writePos)
+				n, err = r.src.Read(r.buf[writePos : writePos+maxWrite])
 			}
 		} else {
-			n, err = r.src.Read(r.buf[writePos : readPos-1])
+			maxWrite := math2.Min(r.maxPerRead, readPos-1-writePos)
+			n, err = r.src.Read(r.buf[writePos : writePos+maxWrite])
 		}
 
 		// 无论成功还是失败，都发送一下信号通知读取端

utils/io2/ring_test.go

@@ -41,7 +41,7 @@ func (r *syncReader) Close() error {
 
 func Test_RingBuffer(t *testing.T) {
 	Convey("写满读满", t, func() {
-		b := RingBuffer(io.NopCloser(bytes.NewBuffer([]byte{1, 2, 3})), 4)
+		b := Ring(io.NopCloser(bytes.NewBuffer([]byte{1, 2, 3})), 4)
 
 		ret := make([]byte, 3)
 		n, err := b.Read(ret)
@@ -53,7 +53,7 @@ func Test_RingBuffer(t *testing.T) {
 	Convey("1+3+1", t, func() {
 		sy := sync2.NewCounterCond(0)
 
-		b := RingBuffer(&syncReader{
+		b := Ring(&syncReader{
 			data: [][]byte{
 				{1},
 				nil,
@@ -84,7 +84,7 @@ func Test_RingBuffer(t *testing.T) {
 	Convey("3+1+2", t, func() {
 		sy := sync2.NewCounterCond(0)
 
-		b := RingBuffer(&syncReader{
+		b := Ring(&syncReader{
 			data: [][]byte{
 				{1, 2, 3, 4, 5, 6},
 			},