commit 2d2fdd1e548fef9bec288fdefcaf3241dafd9f4f
author haoyuewang <haoyuewang@google.com> Wed Sep 16 11:26:56 2020 -0700
committer Copybara-Service <copybara-worker@google.com> Wed Sep 16 11:27:39 2020 -0700
tree b70d5fe481d4b0371f0aa9e89587da30ca521085
parent de9ad9f219c5f211c62f4d57292e86ab236d6d9d

Add a kAFFE client option to enable the usage of AckFrequencyFrame, including
(1) Send min_ack_delay from client.
(2) Update client upon receiving AckFrequencyFrame.

Separate options will enable actual sending of AckFrequencyFrame and is in follow-up CLs.

PiperOrigin-RevId: 332049097
Change-Id: Ibc267ab580ce7ed5638fd2ad62226f67c1604a85

quic/core/quic_received_packet_manager.cc

diff --git a/quic/core/quic_received_packet_manager.cc b/quic/core/quic_received_packet_manager.cc
index 1c9218a..9a84d97 100644
--- a/quic/core/quic_received_packet_manager.cc
+++ b/quic/core/quic_received_packet_manager.cc
@@ -47,11 +47,13 @@
       ack_decimation_delay_(kAckDecimationDelay),
       unlimited_ack_decimation_(false),
       one_immediate_ack_(false),
+      ignore_order_(false),
       local_max_ack_delay_(
           QuicTime::Delta::FromMilliseconds(kDefaultDelayedAckTimeMs)),
       ack_timeout_(QuicTime::Zero()),
       time_of_previous_received_packet_(QuicTime::Zero()),
-      was_last_packet_missing_(false) {}
+      was_last_packet_missing_(false),
+      last_ack_frequency_frame_sequence_number_(-1) {}
 
 QuicReceivedPacketManager::~QuicReceivedPacketManager() {}
 
@@ -194,8 +196,9 @@
 QuicTime::Delta QuicReceivedPacketManager::GetMaxAckDelay(
     QuicPacketNumber last_received_packet_number,
     const RttStats& rtt_stats) const {
-  if (last_received_packet_number <
-      PeerFirstSendingPacketNumber() + min_received_before_ack_decimation_) {
+  if (AckFrequencyFrameReceived() ||
+      last_received_packet_number < PeerFirstSendingPacketNumber() +
+                                        min_received_before_ack_decimation_) {
     return local_max_ack_delay_;
   }
 
@@ -212,6 +215,11 @@
 
 void QuicReceivedPacketManager::MaybeUpdateAckFrequency(
     QuicPacketNumber last_received_packet_number) {
+  if (AckFrequencyFrameReceived()) {
+    // Skip Ack Decimation below after receiving an AckFrequencyFrame from the
+    // other end point.
+    return;
+  }
   if (last_received_packet_number <
       PeerFirstSendingPacketNumber() + min_received_before_ack_decimation_) {
     return;
@@ -231,7 +239,8 @@
     return;
   }
 
-  if (was_last_packet_missing_ && last_sent_largest_acked_.IsInitialized() &&
+  if (!ignore_order_ && was_last_packet_missing_ &&
+      last_sent_largest_acked_.IsInitialized() &&
       last_received_packet_number < last_sent_largest_acked_) {
     // Only ack immediately if an ACK frame was sent with a larger largest acked
     // than the newly received packet number.
@@ -252,7 +261,7 @@
     return;
   }
 
-  if (HasNewMissingPackets()) {
+  if (!ignore_order_ && HasNewMissingPackets()) {
     ack_timeout_ = now;
     return;
   }
@@ -314,4 +323,17 @@
   return ack_frame_.packets.Empty();
 }
 
+void QuicReceivedPacketManager::OnAckFrequencyFrame(
+    const QuicAckFrequencyFrame& frame) {
+  int64_t new_sequence_number = frame.sequence_number;
+  if (new_sequence_number <= last_ack_frequency_frame_sequence_number_) {
+    // Ignore old ACK_FREQUENCY frames.
+    return;
+  }
+  last_ack_frequency_frame_sequence_number_ = new_sequence_number;
+  ack_frequency_ = frame.packet_tolerance;
+  local_max_ack_delay_ = frame.max_ack_delay;
+  ignore_order_ = frame.ignore_order;
+}
+
 }  // namespace quic