Buffer optimizations (#355)

* Avoid creating buffer if pkt larger than ClientNetWriteBufferSize

* Use mempool for Properties Encode

* Use the more efficient Write instead of Write for Buffer to Buffer write

---------

Co-authored-by: JB <28275108+mochi-co@users.noreply.github.com>

clients.go

@@ -582,7 +582,7 @@ func (cl *Client) WritePacket(pk packets.Packet) error {
 		return packets.ErrPacketTooLarge // [MQTT-3.1.2-24] [MQTT-3.1.2-25]
 	}
 
-	n, err := func() (n int64, err error) {
+	n, err := func() (int64, error) {
 		cl.Lock()
 		defer cl.Unlock()
 		if len(cl.State.outbound) == 0 {
@@ -591,23 +591,26 @@ func (cl *Client) WritePacket(pk packets.Packet) error {
 			}
 
 			// first write to buffer, then flush buffer
-			n, _ = buf.WriteTo(cl.Net.outbuf) // will always be successful
+			n, _ := cl.Net.outbuf.Write(buf.Bytes()) // will always be successful
 			err = cl.flushOutbuf()
-			return
+			return int64(n), err
 		}
 
 		// there are more writes in the queue
 		if cl.Net.outbuf == nil {
+			if buf.Len() >= cl.ops.options.ClientNetWriteBufferSize {
+				return buf.WriteTo(cl.Net.Conn)
+			}
 			cl.Net.outbuf = new(bytes.Buffer)
 		}
 
-		n, _ = buf.WriteTo(cl.Net.outbuf) // will always be successful
+		n, _ := cl.Net.outbuf.Write(buf.Bytes()) // will always be successful
 		if cl.Net.outbuf.Len() < cl.ops.options.ClientNetWriteBufferSize {
-			return
+			return int64(n), nil
 		}
 
 		err = cl.flushOutbuf()
-		return
+		return int64(n), err
 	}()
 	if err != nil {
 		return err

packets/packets.go

@@ -348,7 +348,7 @@ func (pk *Packet) ConnectEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -512,7 +512,8 @@ func (pk *Packet) ConnackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
+
 	return nil
 }
 
@@ -557,7 +558,7 @@ func (pk *Packet) DisconnectEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -628,7 +629,7 @@ func (pk *Packet) PublishEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len() + len(pk.Payload)
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 	buf.Write(pk.Payload)
 
 	return nil
@@ -719,7 +720,7 @@ func (pk *Packet) encodePubAckRelRecComp(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 	return nil
 }
 
@@ -858,7 +859,7 @@ func (pk *Packet) SubackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -918,7 +919,7 @@ func (pk *Packet) SubscribeEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -1014,7 +1015,7 @@ func (pk *Packet) UnsubackEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -1070,7 +1071,7 @@ func (pk *Packet) UnsubscribeEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 
 	return nil
 }
@@ -1132,7 +1133,7 @@ func (pk *Packet) AuthEncode(buf *bytes.Buffer) error {
 
 	pk.FixedHeader.Remaining = nb.Len()
 	pk.FixedHeader.Encode(buf)
-	_, _ = nb.WriteTo(buf)
+	buf.Write(nb.Bytes())
 	return nil
 }
 

packets/properties.go

@@ -8,6 +8,8 @@ import (
 	"bytes"
 	"fmt"
 	"strings"
+
+	"github.com/mochi-mqtt/server/v2/mempool"
 )
 
 const (
@@ -199,7 +201,8 @@ func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
 		return
 	}
 
-	var buf bytes.Buffer
+	buf := mempool.GetBuffer()
+	defer mempool.PutBuffer(buf)
 	if p.canEncode(pkt, PropPayloadFormat) && p.PayloadFormatFlag {
 		buf.WriteByte(PropPayloadFormat)
 		buf.WriteByte(p.PayloadFormat)
@@ -230,7 +233,7 @@ func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
 		for _, v := range p.SubscriptionIdentifier {
 			if v > 0 {
 				buf.WriteByte(PropSubscriptionIdentifier)
-				encodeLength(&buf, int64(v))
+				encodeLength(buf, int64(v))
 			}
 		}
 	}
@@ -321,7 +324,8 @@ func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
 	}
 
 	if !mods.DisallowProblemInfo && p.canEncode(pkt, PropUser) {
-		pb := bytes.NewBuffer([]byte{})
+		pb := mempool.GetBuffer()
+		defer mempool.PutBuffer(pb)
 		for _, v := range p.User {
 			pb.WriteByte(PropUser)
 			pb.Write(encodeString(v.Key))
@@ -355,7 +359,7 @@ func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
 	}
 
 	encodeLength(b, int64(buf.Len()))
-	_, _ = buf.WriteTo(b) // [MQTT-3.1.3-10]
+	b.Write(buf.Bytes()) // [MQTT-3.1.3-10]
 }
 
 // Decode decodes property bytes into a properties struct.