net/http: don't spin on temporary accept failure

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5658049

src/pkg/net/http/server.go

@@ -1007,15 +1007,26 @@ func (srv *Server) ListenAndServe() error {
 // then call srv.Handler to reply to them.
 func (srv *Server) Serve(l net.Listener) error {
 	defer l.Close()
+	var tempDelay time.Duration // how long to sleep on accept failure
 	for {
 		rw, e := l.Accept()
 		if e != nil {
 			if ne, ok := e.(net.Error); ok && ne.Temporary() {
-				log.Printf("http: Accept error: %v", e)
+				if tempDelay == 0 {
+					tempDelay = 5 * time.Millisecond
+				} else {
+					tempDelay *= 2
+				}
+				if max := 1 * time.Second; tempDelay > max {
+					tempDelay = max
+				}
+				log.Printf("http: Accept error: %v; retrying in %v", e, tempDelay)
+				time.Sleep(tempDelay)
 				continue
 			}
 			return e
 		}
+		tempDelay = 0
 		if srv.ReadTimeout != 0 {
 			rw.SetReadDeadline(time.Now().Add(srv.ReadTimeout))
 		}