Deprecate FLAGS_quic_simplify_loss_detection.

net/quic/congestion_control/general_loss_algorithm_test.cc

 // Copyright 2015 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.
 
 #include "net/quic/congestion_control/general_loss_algorithm.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "net/quic/congestion_control/rtt_stats.h"
@@ skipping 54 matching lines @@
 };
 
 TEST_F(GeneralLossAlgorithmTest, NackRetransmit1Packet) {
   const size_t kNumSentPackets = 5;
   // Transmit 5 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   // No loss on one ack.
   unacked_packets_.RemoveFromInFlight(2);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 1);
-  }
   VerifyLosses(2, nullptr, 0);
   // No loss on two acks.
   unacked_packets_.RemoveFromInFlight(3);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 2);
-  }
   VerifyLosses(3, nullptr, 0);
   // Loss on three acks.
   unacked_packets_.RemoveFromInFlight(4);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 3);
-  }
   QuicPacketNumber lost[] = {1};
   VerifyLosses(4, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 // A stretch ack is an ack that covers more than 1 packet of previously
 // unacknowledged data.
 TEST_F(GeneralLossAlgorithmTest, NackRetransmit1PacketWith1StretchAck) {
   const size_t kNumSentPackets = 10;
   // Transmit 10 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
 
   // Nack the first packet 3 times in a single StretchAck.
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 3);
-  }
   unacked_packets_.RemoveFromInFlight(2);
   unacked_packets_.RemoveFromInFlight(3);
   unacked_packets_.RemoveFromInFlight(4);
   QuicPacketNumber lost[] = {1};
   VerifyLosses(4, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 // Ack a packet 3 packets ahead, causing a retransmit.
 TEST_F(GeneralLossAlgorithmTest, NackRetransmit1PacketSingleAck) {
   const size_t kNumSentPackets = 10;
   // Transmit 10 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
 
   // Nack the first packet 3 times in an AckFrame with three missing packets.
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 3);
-    unacked_packets_.NackPacket(2, 2);
-    unacked_packets_.NackPacket(3, 1);
-  }
   unacked_packets_.RemoveFromInFlight(4);
   QuicPacketNumber lost[] = {1};
   VerifyLosses(4, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(GeneralLossAlgorithmTest, EarlyRetransmit1Packet) {
   const size_t kNumSentPackets = 2;
   // Transmit 2 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   // Early retransmit when the final packet gets acked and the first is nacked.
   unacked_packets_.RemoveFromInFlight(2);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 1);
-  }
   VerifyLosses(2, nullptr, 0);
   EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt().Multiply(1.25)),
             loss_algorithm_.GetLossTimeout());
 
   clock_.AdvanceTime(rtt_stats_.latest_rtt().Multiply(1.25));
   QuicPacketNumber lost[] = {1};
   VerifyLosses(2, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(GeneralLossAlgorithmTest, EarlyRetransmitAllPackets) {
   const size_t kNumSentPackets = 5;
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
     // Advance the time 1/4 RTT between 3 and 4.
     if (i == 3) {
       clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
     }
   }
 
   // Early retransmit when the final packet gets acked and 1.25 RTTs have
   // elapsed since the packets were sent.
   unacked_packets_.RemoveFromInFlight(kNumSentPackets);
   // This simulates a single ack following multiple missing packets with FACK.
-  if (!FLAGS_quic_simplify_loss_detection) {
-    for (size_t i = 1; i < kNumSentPackets; ++i) {
-      unacked_packets_.NackPacket(i, kNumSentPackets - i);
-    }
-  }
   QuicPacketNumber lost[] = {1, 2};
   VerifyLosses(kNumSentPackets, lost, arraysize(lost));
   // The time has already advanced 1/4 an RTT, so ensure the timeout is set
   // 1.25 RTTs after the earliest pending packet(3), not the last(4).
   EXPECT_EQ(clock_.Now().Add(rtt_stats_.smoothed_rtt()),
             loss_algorithm_.GetLossTimeout());
 
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
   QuicPacketNumber lost2[] = {1, 2, 3};
   VerifyLosses(kNumSentPackets, lost2, arraysize(lost2));
@@ skipping 10 matching lines @@
   // Transmit 2 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   // Neuter packet 1.
   unacked_packets_.RemoveRetransmittability(1);
 
   // Early retransmit when the final packet gets acked and the first is nacked.
   unacked_packets_.IncreaseLargestObserved(2);
   unacked_packets_.RemoveFromInFlight(2);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 1);
-  }
   VerifyLosses(2, nullptr, 0);
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(GeneralLossAlgorithmTest, AlwaysLosePacketSent1RTTEarlier) {
   // Transmit 1 packet and then wait an rtt plus 1ms.
   SendDataPacket(1);
   clock_.AdvanceTime(
       rtt_stats_.smoothed_rtt().Add(QuicTime::Delta::FromMilliseconds(1)));
 
   // Transmit 2 packets.
   SendDataPacket(2);
   SendDataPacket(3);
 
   // Wait another RTT and ack 2.
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
   unacked_packets_.IncreaseLargestObserved(2);
   unacked_packets_.RemoveFromInFlight(2);
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 1);
-  }
   QuicPacketNumber lost[] = {1};
   VerifyLosses(2, lost, arraysize(lost));
 }
 
 // Time-based loss detection tests.
 TEST_F(GeneralLossAlgorithmTest, NoLossFor500Nacks) {
   loss_algorithm_.SetLossDetectionType(kTime);
   const size_t kNumSentPackets = 5;
   // Transmit 5 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   unacked_packets_.RemoveFromInFlight(2);
   for (size_t i = 1; i < 500; ++i) {
-    if (!FLAGS_quic_simplify_loss_detection) {
-      unacked_packets_.NackPacket(1, i);
-    }
     VerifyLosses(2, nullptr, 0);
   }
   EXPECT_EQ(rtt_stats_.smoothed_rtt().Multiply(1.25),
             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
 }
 
 TEST_F(GeneralLossAlgorithmTest, NoLossUntilTimeout) {
   loss_algorithm_.SetLossDetectionType(kTime);
   const size_t kNumSentPackets = 10;
   // Transmit 10 packets at 1/10th an RTT interval.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
     clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.1));
   }
   // Expect the timer to not be set.
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
   // The packet should not be lost until 1.25 RTTs pass.
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 1);
-  }
   unacked_packets_.RemoveFromInFlight(2);
   VerifyLosses(2, nullptr, 0);
   // Expect the timer to be set to 0.25 RTT's in the future.
   EXPECT_EQ(rtt_stats_.smoothed_rtt().Multiply(0.25),
             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
-  if (!FLAGS_quic_simplify_loss_detection) {
-    unacked_packets_.NackPacket(1, 5);
-  }
   VerifyLosses(2, nullptr, 0);
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
   QuicPacketNumber lost[] = {1};
   VerifyLosses(2, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(GeneralLossAlgorithmTest, NoLossWithoutNack) {
   loss_algorithm_.SetLossDetectionType(kTime);
   const size_t kNumSentPackets = 10;
@@ skipping 21 matching lines @@
   loss_algorithm_.SetLossDetectionType(kTime);
   const size_t kNumSentPackets = 10;
   // Transmit 10 packets at once and then go forward an RTT.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
   // Expect the timer to not be set.
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
   // The packet should not be lost until 1.25 RTTs pass.
-  if (!FLAGS_quic_simplify_loss_detection) {
-    for (size_t i = 1; i < kNumSentPackets; ++i) {
-      unacked_packets_.NackPacket(i, 1);
-    }
-  }
   unacked_packets_.RemoveFromInFlight(10);
   VerifyLosses(10, nullptr, 0);
   // Expect the timer to be set to 0.25 RTT's in the future.
   EXPECT_EQ(rtt_stats_.smoothed_rtt().Multiply(0.25),
             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
   QuicPacketNumber lost[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
   VerifyLosses(10, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(GeneralLossAlgorithmTest, NoSpuriousLossesFromLargeReordering) {
-  FLAGS_quic_simplify_loss_detection = true;
   FLAGS_quic_loss_recovery_use_largest_acked = true;
   loss_algorithm_.SetLossDetectionType(kTime);
   const size_t kNumSentPackets = 10;
   // Transmit 10 packets at once and then go forward an RTT.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt());
   // Expect the timer to not be set.
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
   // The packet should not be lost until 1.25 RTTs pass.
 
   unacked_packets_.RemoveFromInFlight(10);
   VerifyLosses(10, nullptr, 0);
   // Expect the timer to be set to 0.25 RTT's in the future.
   EXPECT_EQ(rtt_stats_.smoothed_rtt().Multiply(0.25),
             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
   clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.25));
   // Now ack packets 1 to 9 and ensure the timer is no longer set and no packets
   // are lost.
   for (QuicPacketNumber i = 1; i <= 9; ++i) {
     unacked_packets_.RemoveFromInFlight(i);
     VerifyLosses(i, nullptr, 0);
     EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
   }
 }
 
 TEST_F(GeneralLossAlgorithmTest, IncreaseThresholdUponSpuriousLoss) {
-  FLAGS_quic_simplify_loss_detection = true;
   FLAGS_quic_adaptive_loss_recovery = true;
   loss_algorithm_.SetLossDetectionType(kAdaptiveTime);
   EXPECT_EQ(16, loss_algorithm_.reordering_fraction());
   const size_t kNumSentPackets = 10;
   // Transmit 2 packets at 1/10th an RTT interval.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
     clock_.AdvanceTime(rtt_stats_.smoothed_rtt().Multiply(0.1));
   }
   EXPECT_EQ(QuicTime::Zero().Add(rtt_stats_.smoothed_rtt()), clock_.Now());
@@ skipping 25 matching lines @@
   // Detect another spurious retransmit and ensure the threshold doesn't
   // increase again.
   loss_algorithm_.SpuriousRetransmitDetected(unacked_packets_, clock_.Now(),
                                              rtt_stats_, 12);
   EXPECT_EQ(2, loss_algorithm_.reordering_fraction());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net