Improved server performance

server/game/Router.go

@@ -15,7 +15,7 @@ func (ph *Router) Get(code byte, handler Handler) {
 }
 
 // handle deals with an incoming packet.
-func (ph *Router) handle(p *Packet) {
+func (ph *Router) handle(p Packet) {
 	defer func() {
 		if r := recover(); r != nil {
 			fmt.Println(p)

server/game/Server.go

@@ -5,20 +5,26 @@ import (
 	"net"
 )
 
-const ChannelBufferSize = 4096
+const (
+	// How many packets we will buffer in case our consumer can't keep up.
+	ChannelBufferSize = 4096
+
+	// The maximum data length of a UDP datagram (8 bytes UDP header, 20 bytes IP header).
+	UDPDataMaxLength = 65535 - 8 - 20
+)
 
 // Server represents a UDP server.
 type Server struct {
 	handlers    [256]Handler
 	socket      *net.UDPConn
-	incoming    chan *Packet
+	incoming    chan Packet
 	packetCount int
 }
 
 // NewServer creates a new server.
 func NewServer() *Server {
 	return &Server{
-		incoming: make(chan *Packet, ChannelBufferSize),
+		incoming: make(chan Packet, ChannelBufferSize),
 	}
 }
 
@@ -47,8 +53,10 @@ func (s *Server) ResetPacketCount() {
 
 // Send sends the data prefixed with the byte code to the client.
 func (s *Server) Send(code byte, data []byte, address *net.UDPAddr) error {
-	data = append([]byte{code}, data...)
+	tmp := make([]byte, len(data)+1)
-	_, err := s.socket.WriteToUDP(data, address)
+	tmp[0] = code
+	copy(tmp[1:], data)
+	_, err := s.socket.WriteToUDP(tmp, address)
 	return err
 }
 
@@ -71,7 +79,7 @@ func listen(port int) *net.UDPConn {
 
 // read is a blocking call which will read incoming packets and handle them.
 func (s *Server) read() {
-	buffer := make([]byte, 16384)
+	buffer := make([]byte, UDPDataMaxLength)
 
 	for {
 		n, addr, err := s.socket.ReadFromUDP(buffer)
@@ -87,7 +95,7 @@ func (s *Server) read() {
 
 		tmp := make([]byte, n)
 		copy(tmp, buffer)
-		s.incoming <- &Packet{Data: tmp, Address: addr}
+		s.incoming <- Packet{Data: tmp, Address: addr}
 		s.packetCount++
 	}
 }

server/game/Server_test.go

@@ -0,0 +1,62 @@
+package game_test
+
+import (
+	"server/game"
+	"testing"
+)
+
+var (
+	code = byte(1)
+	data = []byte("Hello")
+)
+
+func BenchmarkSendAppend(b *testing.B) {
+	b.ReportAllocs()
+
+	for i := 0; i < b.N; i++ {
+		tmp := append([]byte{code}, data...)
+		noop(tmp)
+	}
+}
+
+func BenchmarkSendCopy(b *testing.B) {
+	b.ReportAllocs()
+
+	for i := 0; i < b.N; i++ {
+		tmp := make([]byte, len(data)+1)
+		tmp[0] = code
+		copy(tmp[1:], data)
+		noop(tmp)
+	}
+}
+
+func noop([]byte) {}
+
+func BenchmarkReceivePointer(b *testing.B) {
+	b.ReportAllocs()
+	incoming := make(chan *game.Packet, 1)
+
+	for i := 0; i < b.N; i++ {
+		incoming <- &game.Packet{data, nil}
+		packet := <-incoming
+
+		if packet.Data[0] != 'H' {
+			b.FailNow()
+		}
+	}
+}
+
+func BenchmarkReceiveValue(b *testing.B) {
+	b.ReportAllocs()
+	incoming := make(chan game.Packet, 1)
+	data := []byte("Hello")
+
+	for i := 0; i < b.N; i++ {
+		incoming <- game.Packet{data, nil}
+		packet := <-incoming
+
+		if packet.Data[0] != 'H' {
+			b.FailNow()
+		}
+	}
+}