Add a new QUIC Ack Decimation mode that is reordering tolerant. Protected by FLAG_quic_ack_decimati…

net/quic/quic_connection.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // The entity that handles framing writes for a Quic client or server.
 // Each QuicSession will have a connection associated with it.
 //
 // On the server side, the Dispatcher handles the raw reads, and hands off
 // packets via ProcessUdpPacket for framing and processing.
 //
@@ skipping 289 matching lines @@
       public QuicBlockedWriterInterface,
       public QuicPacketGenerator::DelegateInterface,
       public QuicSentPacketManager::NetworkChangeVisitor {
  public:
   enum AckBundling {
     NO_ACK = 0,
     SEND_ACK = 1,
     BUNDLE_PENDING_ACK = 2,
   };
 
+  enum AckMode { TCP_ACKING, ACK_DECIMATION, ACK_DECIMATION_WITH_REORDERING };
+
   // Constructs a new QuicConnection for |connection_id| and |address| using
   // |writer| to write packets. |owns_writer| specifies whether the connection
   // takes ownership of |writer|. |helper| must outlive this connection.
   QuicConnection(QuicConnectionId connection_id,
                  IPEndPoint address,
                  QuicConnectionHelperInterface* helper,
                  QuicPacketWriter* writer,
                  bool owns_writer,
                  Perspective perspective,
                  const QuicVersionVector& supported_versions);
@@ skipping 592 matching lines @@
 
   FecGroupMap group_map_;
 
   QuicReceivedPacketManager received_packet_manager_;
   QuicSentEntropyManager sent_entropy_manager_;
 
   // Indicates whether an ack should be sent the next time we try to write.
   bool ack_queued_;
   // How many retransmittable packets have arrived without sending an ack.
   QuicPacketCount num_retransmittable_packets_received_since_last_ack_sent_;
+  // Whether there were missing packets in the last sent ack.
+  bool last_ack_had_missing_packets_;
   // How many consecutive packets have arrived without sending an ack.
   QuicPacketCount num_packets_received_since_last_ack_sent_;
   // Indicates how many consecutive times an ack has arrived which indicates
   // the peer needs to stop waiting for some packets.
   int stop_waiting_count_;
-  // When true, ack only every 10 packets as long as they arrive close together.
-  bool ack_decimation_enabled_;
+  // Indicates the current ack mode, defaults to acking every 2 packets.
+  AckMode ack_mode_;
 
   // Indicates the retransmit alarm is going to be set by the
   // ScopedRetransmitAlarmDelayer
   bool delay_setting_retransmission_alarm_;
   // Indicates the retransmission alarm needs to be set.
   bool pending_retransmission_alarm_;
 
   // Arena to store class implementations within the QuicConnection.
   QuicConnectionArena arena_;
 
@@ skipping 114 matching lines @@
 
   // If true, multipath is enabled for this connection.
   bool multipath_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicConnection);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CONNECTION_H_