net/quic/congestion_control/time_loss_algorithm_test.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <algorithm>
   6
   7 #include "base/logging.h"
   8 #include "base/stl_util.h"
   9 #include "net/quic/congestion_control/rtt_stats.h"
  10 #include "net/quic/congestion_control/time_loss_algorithm.h"
  11 #include "net/quic/quic_unacked_packet_map.h"
  12 #include "net/quic/test_tools/mock_clock.h"
  13 #include "testing/gtest/include/gtest/gtest.h"
  14
  15 namespace net {
  16 namespace test {
  17
  18 class TimeLossAlgorithmTest : public ::testing::Test {
  19  protected:
  20   TimeLossAlgorithmTest()
  21       : unacked_packets_() {
  22     rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100),
  23                          QuicTime::Delta::Zero(),
  24                          clock_.Now());
  25   }
  26
  27   void SendDataPacket(QuicPacketSequenceNumber sequence_number) {
  28     SerializedPacket packet(sequence_number, PACKET_1BYTE_SEQUENCE_NUMBER,
  29                             NULL, 0, new RetransmittableFrames());
  30     unacked_packets_.AddPacket(packet);
  31     unacked_packets_.SetSent(sequence_number, clock_.Now(), 1000, true);
  32   }
  33
  34   void VerifyLosses(QuicPacketSequenceNumber largest_observed,
  35                     QuicPacketSequenceNumber* losses_expected,
  36                     size_t num_losses) {
  37     SequenceNumberSet lost_packets =
  38         loss_algorithm_.DetectLostPackets(
  39             unacked_packets_, clock_.Now(), largest_observed, rtt_stats_);
  40     EXPECT_EQ(num_losses, lost_packets.size());
  41     for (size_t i = 0; i < num_losses; ++i) {
  42       EXPECT_TRUE(ContainsKey(lost_packets, losses_expected[i]));
  43     }
  44   }
  45
  46   QuicUnackedPacketMap unacked_packets_;
  47   TimeLossAlgorithm loss_algorithm_;
  48   RttStats rtt_stats_;
  49   MockClock clock_;
  50 };
  51
  52 TEST_F(TimeLossAlgorithmTest, NoLossFor500Nacks) {
  53   const size_t kNumSentPackets = 5;
  54   // Transmit 5 packets.
  55   for (size_t i = 1; i <= kNumSentPackets; ++i) {
  56     SendDataPacket(i);
  57   }
  58   unacked_packets_.RemoveFromInFlight(2);
  59   for (size_t i = 1; i < 500; ++i) {
  60     unacked_packets_.NackPacket(1, i);
  61     VerifyLosses(2, NULL, 0);
  62   }
  63   EXPECT_EQ(rtt_stats_.SmoothedRtt().Multiply(1.25),
  64             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
  65 }
  66
  67 TEST_F(TimeLossAlgorithmTest, NoLossUntilTimeout) {
  68   const size_t kNumSentPackets = 10;
  69   // Transmit 10 packets at 1/10th an RTT interval.
  70   for (size_t i = 1; i <= kNumSentPackets; ++i) {
  71     SendDataPacket(i);
  72     clock_.AdvanceTime(rtt_stats_.SmoothedRtt().Multiply(0.1));
  73   }
  74   // Expect the timer to not be set.
  75   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
  76   // The packet should not be lost until 1.25 RTTs pass.
  77   unacked_packets_.NackPacket(1, 1);
  78   unacked_packets_.RemoveFromInFlight(2);
  79   VerifyLosses(2, NULL, 0);
  80   // Expect the timer to be set to 0.25 RTT's in the future.
  81   EXPECT_EQ(rtt_stats_.SmoothedRtt().Multiply(0.25),
  82             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
  83   unacked_packets_.NackPacket(1, 5);
  84   VerifyLosses(2, NULL, 0);
  85   clock_.AdvanceTime(rtt_stats_.SmoothedRtt().Multiply(0.25));
  86   QuicPacketSequenceNumber lost[] = { 1 };
  87   VerifyLosses(2, lost, arraysize(lost));
  88   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
  89 }
  90
  91 TEST_F(TimeLossAlgorithmTest, NoLossWithoutNack) {
  92   const size_t kNumSentPackets = 10;
  93   // Transmit 10 packets at 1/10th an RTT interval.
  94   for (size_t i = 1; i <= kNumSentPackets; ++i) {
  95     SendDataPacket(i);
  96     clock_.AdvanceTime(rtt_stats_.SmoothedRtt().Multiply(0.1));
  97   }
  98   // Expect the timer to not be set.
  99   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 100   // The packet should not be lost without a nack.
 101   unacked_packets_.RemoveFromInFlight(1);
 102   VerifyLosses(1, NULL, 0);
 103   // The timer should still not be set.
 104   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 105   clock_.AdvanceTime(rtt_stats_.SmoothedRtt().Multiply(0.25));
 106   VerifyLosses(1, NULL, 0);
 107   clock_.AdvanceTime(rtt_stats_.SmoothedRtt());
 108   VerifyLosses(1, NULL, 0);
 109
 110   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 111 }
 112
 113 TEST_F(TimeLossAlgorithmTest, MultipleLossesAtOnce) {
 114   const size_t kNumSentPackets = 10;
 115   // Transmit 10 packets at once and then go forward an RTT.
 116   for (size_t i = 1; i <= kNumSentPackets; ++i) {
 117     SendDataPacket(i);
 118   }
 119   clock_.AdvanceTime(rtt_stats_.SmoothedRtt());
 120   // Expect the timer to not be set.
 121   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 122   // The packet should not be lost until 1.25 RTTs pass.
 123   for (size_t i = 1; i < kNumSentPackets; ++i) {
 124     unacked_packets_.NackPacket(i, 1);
 125   }
 126   unacked_packets_.RemoveFromInFlight(10);
 127   VerifyLosses(10, NULL, 0);
 128   // Expect the timer to be set to 0.25 RTT's in the future.
 129   EXPECT_EQ(rtt_stats_.SmoothedRtt().Multiply(0.25),
 130             loss_algorithm_.GetLossTimeout().Subtract(clock_.Now()));
 131   clock_.AdvanceTime(rtt_stats_.SmoothedRtt().Multiply(0.25));
 132   QuicPacketSequenceNumber lost[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 133   VerifyLosses(10, lost, arraysize(lost));
 134   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 135 }
 136
 137 }  // namespace test
 138 }  // namespace net