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| 1 // Copyright (c) 2012 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 "net/quic/congestion_control/tcp_cubic_sender.h" | |
| 6 | |
| 7 #include <algorithm> | |
| 8 | |
| 9 #include "base/logging.h" | |
| 10 #include "base/memory/scoped_ptr.h" | |
| 11 #include "net/quic/congestion_control/rtt_stats.h" | |
| 12 #include "net/quic/crypto/crypto_protocol.h" | |
| 13 #include "net/quic/proto/cached_network_parameters.pb.h" | |
| 14 #include "net/quic/quic_flags.h" | |
| 15 #include "net/quic/quic_protocol.h" | |
| 16 #include "net/quic/quic_utils.h" | |
| 17 #include "net/quic/test_tools/mock_clock.h" | |
| 18 #include "net/quic/test_tools/quic_config_peer.h" | |
| 19 #include "net/quic/test_tools/quic_test_utils.h" | |
| 20 #include "testing/gtest/include/gtest/gtest.h" | |
| 21 | |
| 22 using std::min; | |
| 23 | |
| 24 namespace net { | |
| 25 namespace test { | |
| 26 | |
| 27 // TODO(ianswett): A number of theses tests were written with the assumption of | |
| 28 // an initial CWND of 10. They have carefully calculated values which should be | |
| 29 // updated to be based on kInitialCongestionWindow. | |
| 30 const uint32_t kInitialCongestionWindowPackets = 10; | |
| 31 const uint32_t kDefaultWindowTCP = | |
| 32 kInitialCongestionWindowPackets * kDefaultTCPMSS; | |
| 33 const float kRenoBeta = 0.7f; // Reno backoff factor. | |
| 34 | |
| 35 class TcpCubicSenderPeer : public TcpCubicSender { | |
| 36 public: | |
| 37 TcpCubicSenderPeer(const QuicClock* clock, | |
| 38 bool reno, | |
| 39 QuicPacketCount max_tcp_congestion_window) | |
| 40 : TcpCubicSender(clock, | |
| 41 &rtt_stats_, | |
| 42 reno, | |
| 43 kInitialCongestionWindowPackets, | |
| 44 max_tcp_congestion_window, | |
| 45 &stats_) {} | |
| 46 | |
| 47 QuicPacketCount congestion_window() { return congestion_window_; } | |
| 48 | |
| 49 QuicPacketCount slowstart_threshold() { return slowstart_threshold_; } | |
| 50 | |
| 51 const HybridSlowStart& hybrid_slow_start() const { | |
| 52 return hybrid_slow_start_; | |
| 53 } | |
| 54 | |
| 55 float GetRenoBeta() const { return RenoBeta(); } | |
| 56 | |
| 57 RttStats rtt_stats_; | |
| 58 QuicConnectionStats stats_; | |
| 59 }; | |
| 60 | |
| 61 class TcpCubicSenderTest : public ::testing::Test { | |
| 62 protected: | |
| 63 TcpCubicSenderTest() | |
| 64 : one_ms_(QuicTime::Delta::FromMilliseconds(1)), | |
| 65 sender_(new TcpCubicSenderPeer(&clock_, true, kMaxCongestionWindow)), | |
| 66 packet_number_(1), | |
| 67 acked_packet_number_(0), | |
| 68 bytes_in_flight_(0) {} | |
| 69 | |
| 70 int SendAvailableSendWindow() { | |
| 71 // Send as long as TimeUntilSend returns Zero. | |
| 72 int packets_sent = 0; | |
| 73 bool can_send = sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 74 HAS_RETRANSMITTABLE_DATA) | |
| 75 .IsZero(); | |
| 76 while (can_send) { | |
| 77 sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, packet_number_++, | |
| 78 kDefaultTCPMSS, HAS_RETRANSMITTABLE_DATA); | |
| 79 ++packets_sent; | |
| 80 bytes_in_flight_ += kDefaultTCPMSS; | |
| 81 can_send = sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 82 HAS_RETRANSMITTABLE_DATA) | |
| 83 .IsZero(); | |
| 84 } | |
| 85 return packets_sent; | |
| 86 } | |
| 87 | |
| 88 // Normal is that TCP acks every other segment. | |
| 89 void AckNPackets(int n) { | |
| 90 sender_->rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(60), | |
| 91 QuicTime::Delta::Zero(), clock_.Now()); | |
| 92 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 93 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 94 for (int i = 0; i < n; ++i) { | |
| 95 ++acked_packet_number_; | |
| 96 acked_packets.push_back( | |
| 97 std::make_pair(acked_packet_number_, kDefaultTCPMSS)); | |
| 98 } | |
| 99 sender_->OnCongestionEvent(true, bytes_in_flight_, acked_packets, | |
| 100 lost_packets); | |
| 101 bytes_in_flight_ -= n * kDefaultTCPMSS; | |
| 102 clock_.AdvanceTime(one_ms_); | |
| 103 } | |
| 104 | |
| 105 void LoseNPackets(int n) { | |
| 106 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 107 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 108 for (int i = 0; i < n; ++i) { | |
| 109 ++acked_packet_number_; | |
| 110 lost_packets.push_back( | |
| 111 std::make_pair(acked_packet_number_, kDefaultTCPMSS)); | |
| 112 } | |
| 113 sender_->OnCongestionEvent(false, bytes_in_flight_, acked_packets, | |
| 114 lost_packets); | |
| 115 bytes_in_flight_ -= n * kDefaultTCPMSS; | |
| 116 } | |
| 117 | |
| 118 // Does not increment acked_packet_number_. | |
| 119 void LosePacket(QuicPacketNumber packet_number) { | |
| 120 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 121 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 122 lost_packets.push_back(std::make_pair(packet_number, kDefaultTCPMSS)); | |
| 123 sender_->OnCongestionEvent(false, bytes_in_flight_, acked_packets, | |
| 124 lost_packets); | |
| 125 bytes_in_flight_ -= kDefaultTCPMSS; | |
| 126 } | |
| 127 | |
| 128 const QuicTime::Delta one_ms_; | |
| 129 MockClock clock_; | |
| 130 scoped_ptr<TcpCubicSenderPeer> sender_; | |
| 131 QuicPacketNumber packet_number_; | |
| 132 QuicPacketNumber acked_packet_number_; | |
| 133 QuicByteCount bytes_in_flight_; | |
| 134 }; | |
| 135 | |
| 136 TEST_F(TcpCubicSenderTest, SimpleSender) { | |
| 137 // At startup make sure we are at the default. | |
| 138 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 139 // At startup make sure we can send. | |
| 140 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 141 .IsZero()); | |
| 142 // Make sure we can send. | |
| 143 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 144 .IsZero()); | |
| 145 // And that window is un-affected. | |
| 146 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 147 | |
| 148 // Fill the send window with data, then verify that we can't send. | |
| 149 SendAvailableSendWindow(); | |
| 150 EXPECT_FALSE(sender_->TimeUntilSend(clock_.Now(), | |
| 151 sender_->GetCongestionWindow(), | |
| 152 HAS_RETRANSMITTABLE_DATA) | |
| 153 .IsZero()); | |
| 154 } | |
| 155 | |
| 156 TEST_F(TcpCubicSenderTest, ApplicationLimitedSlowStart) { | |
| 157 // Send exactly 10 packets and ensure the CWND ends at 14 packets. | |
| 158 const int kNumberOfAcks = 5; | |
| 159 // At startup make sure we can send. | |
| 160 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 161 .IsZero()); | |
| 162 // Make sure we can send. | |
| 163 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 164 .IsZero()); | |
| 165 | |
| 166 SendAvailableSendWindow(); | |
| 167 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 168 AckNPackets(2); | |
| 169 } | |
| 170 QuicByteCount bytes_to_send = sender_->GetCongestionWindow(); | |
| 171 // It's expected 2 acks will arrive when the bytes_in_flight are greater than | |
| 172 // half the CWND. | |
| 173 EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * 2, bytes_to_send); | |
| 174 } | |
| 175 | |
| 176 TEST_F(TcpCubicSenderTest, ExponentialSlowStart) { | |
| 177 const int kNumberOfAcks = 20; | |
| 178 // At startup make sure we can send. | |
| 179 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 180 .IsZero()); | |
| 181 EXPECT_EQ(QuicBandwidth::Zero(), sender_->BandwidthEstimate()); | |
| 182 // Make sure we can send. | |
| 183 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 184 .IsZero()); | |
| 185 | |
| 186 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 187 // Send our full send window. | |
| 188 SendAvailableSendWindow(); | |
| 189 AckNPackets(2); | |
| 190 } | |
| 191 const QuicByteCount cwnd = sender_->GetCongestionWindow(); | |
| 192 EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * kNumberOfAcks, cwnd); | |
| 193 EXPECT_EQ(QuicBandwidth::FromBytesAndTimeDelta( | |
| 194 cwnd, sender_->rtt_stats_.smoothed_rtt()), | |
| 195 sender_->BandwidthEstimate()); | |
| 196 } | |
| 197 | |
| 198 TEST_F(TcpCubicSenderTest, SlowStartPacketLoss) { | |
| 199 sender_->SetNumEmulatedConnections(1); | |
| 200 const int kNumberOfAcks = 10; | |
| 201 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 202 // Send our full send window. | |
| 203 SendAvailableSendWindow(); | |
| 204 AckNPackets(2); | |
| 205 } | |
| 206 SendAvailableSendWindow(); | |
| 207 QuicByteCount expected_send_window = | |
| 208 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 209 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 210 | |
| 211 // Lose a packet to exit slow start. | |
| 212 LoseNPackets(1); | |
| 213 size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; | |
| 214 | |
| 215 // We should now have fallen out of slow start with a reduced window. | |
| 216 expected_send_window *= kRenoBeta; | |
| 217 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 218 | |
| 219 // Recovery phase. We need to ack every packet in the recovery window before | |
| 220 // we exit recovery. | |
| 221 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 222 DVLOG(1) << "number_packets: " << number_of_packets_in_window; | |
| 223 AckNPackets(packets_in_recovery_window); | |
| 224 SendAvailableSendWindow(); | |
| 225 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 226 | |
| 227 // We need to ack an entire window before we increase CWND by 1. | |
| 228 AckNPackets(number_of_packets_in_window - 2); | |
| 229 SendAvailableSendWindow(); | |
| 230 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 231 | |
| 232 // Next ack should increase cwnd by 1. | |
| 233 AckNPackets(1); | |
| 234 expected_send_window += kDefaultTCPMSS; | |
| 235 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 236 | |
| 237 // Now RTO and ensure slow start gets reset. | |
| 238 EXPECT_TRUE(sender_->hybrid_slow_start().started()); | |
| 239 sender_->OnRetransmissionTimeout(true); | |
| 240 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 241 } | |
| 242 | |
| 243 TEST_F(TcpCubicSenderTest, SlowStartPacketLossWithLargeReduction) { | |
| 244 QuicConfig config; | |
| 245 QuicTagVector options; | |
| 246 options.push_back(kSSLR); | |
| 247 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 248 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 249 | |
| 250 sender_->SetNumEmulatedConnections(1); | |
| 251 const int kNumberOfAcks = 10; | |
| 252 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 253 // Send our full send window. | |
| 254 SendAvailableSendWindow(); | |
| 255 AckNPackets(2); | |
| 256 } | |
| 257 SendAvailableSendWindow(); | |
| 258 QuicByteCount expected_send_window = | |
| 259 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 260 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 261 | |
| 262 // Lose a packet to exit slow start. We should now have fallen out of | |
| 263 // slow start with a window reduced by 1. | |
| 264 LoseNPackets(1); | |
| 265 expected_send_window -= kDefaultTCPMSS; | |
| 266 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 267 | |
| 268 // Lose 5 packets in recovery and verify that congestion window is reduced | |
| 269 // further. | |
| 270 LoseNPackets(5); | |
| 271 expected_send_window -= 5 * kDefaultTCPMSS; | |
| 272 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 273 | |
| 274 size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; | |
| 275 | |
| 276 // Recovery phase. We need to ack every packet in the recovery window before | |
| 277 // we exit recovery. | |
| 278 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 279 DVLOG(1) << "number_packets: " << number_of_packets_in_window; | |
| 280 AckNPackets(packets_in_recovery_window); | |
| 281 SendAvailableSendWindow(); | |
| 282 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 283 | |
| 284 // We need to ack the rest of the window before cwnd increases by 1. | |
| 285 AckNPackets(number_of_packets_in_window - 1); | |
| 286 SendAvailableSendWindow(); | |
| 287 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 288 | |
| 289 // Next ack should increase cwnd by 1. | |
| 290 AckNPackets(1); | |
| 291 expected_send_window += kDefaultTCPMSS; | |
| 292 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 293 | |
| 294 // Now RTO and ensure slow start gets reset. | |
| 295 EXPECT_TRUE(sender_->hybrid_slow_start().started()); | |
| 296 sender_->OnRetransmissionTimeout(true); | |
| 297 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 298 } | |
| 299 | |
| 300 TEST_F(TcpCubicSenderTest, NoPRRWhenLessThanOnePacketInFlight) { | |
| 301 SendAvailableSendWindow(); | |
| 302 LoseNPackets(kInitialCongestionWindowPackets - 1); | |
| 303 AckNPackets(1); | |
| 304 // PRR will allow 2 packets for every ack during recovery. | |
| 305 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 306 // Simulate abandoning all packets by supplying a bytes_in_flight of 0. | |
| 307 // PRR should now allow a packet to be sent, even though prr's state | |
| 308 // variables believe it has sent enough packets. | |
| 309 EXPECT_EQ(QuicTime::Delta::Zero(), | |
| 310 sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA)); | |
| 311 } | |
| 312 | |
| 313 TEST_F(TcpCubicSenderTest, SlowStartPacketLossPRR) { | |
| 314 sender_->SetNumEmulatedConnections(1); | |
| 315 // Test based on the first example in RFC6937. | |
| 316 // Ack 10 packets in 5 acks to raise the CWND to 20, as in the example. | |
| 317 const int kNumberOfAcks = 5; | |
| 318 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 319 // Send our full send window. | |
| 320 SendAvailableSendWindow(); | |
| 321 AckNPackets(2); | |
| 322 } | |
| 323 SendAvailableSendWindow(); | |
| 324 QuicByteCount expected_send_window = | |
| 325 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 326 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 327 | |
| 328 LoseNPackets(1); | |
| 329 | |
| 330 // We should now have fallen out of slow start with a reduced window. | |
| 331 size_t send_window_before_loss = expected_send_window; | |
| 332 expected_send_window *= kRenoBeta; | |
| 333 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 334 | |
| 335 // Testing TCP proportional rate reduction. | |
| 336 // We should send packets paced over the received acks for the remaining | |
| 337 // outstanding packets. The number of packets before we exit recovery is the | |
| 338 // original CWND minus the packet that has been lost and the one which | |
| 339 // triggered the loss. | |
| 340 size_t remaining_packets_in_recovery = | |
| 341 send_window_before_loss / kDefaultTCPMSS - 2; | |
| 342 | |
| 343 for (size_t i = 0; i < remaining_packets_in_recovery; ++i) { | |
| 344 AckNPackets(1); | |
| 345 SendAvailableSendWindow(); | |
| 346 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 347 } | |
| 348 | |
| 349 // We need to ack another window before we increase CWND by 1. | |
| 350 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 351 for (size_t i = 0; i < number_of_packets_in_window; ++i) { | |
| 352 AckNPackets(1); | |
| 353 EXPECT_EQ(1, SendAvailableSendWindow()); | |
| 354 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 355 } | |
| 356 | |
| 357 AckNPackets(1); | |
| 358 expected_send_window += kDefaultTCPMSS; | |
| 359 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 360 } | |
| 361 | |
| 362 TEST_F(TcpCubicSenderTest, SlowStartBurstPacketLossPRR) { | |
| 363 sender_->SetNumEmulatedConnections(1); | |
| 364 // Test based on the second example in RFC6937, though we also implement | |
| 365 // forward acknowledgements, so the first two incoming acks will trigger | |
| 366 // PRR immediately. | |
| 367 // Ack 20 packets in 10 acks to raise the CWND to 30. | |
| 368 const int kNumberOfAcks = 10; | |
| 369 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 370 // Send our full send window. | |
| 371 SendAvailableSendWindow(); | |
| 372 AckNPackets(2); | |
| 373 } | |
| 374 SendAvailableSendWindow(); | |
| 375 QuicByteCount expected_send_window = | |
| 376 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 377 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 378 | |
| 379 // Lose one more than the congestion window reduction, so that after loss, | |
| 380 // bytes_in_flight is lesser than the congestion window. | |
| 381 size_t send_window_after_loss = kRenoBeta * expected_send_window; | |
| 382 size_t num_packets_to_lose = | |
| 383 (expected_send_window - send_window_after_loss) / kDefaultTCPMSS + 1; | |
| 384 LoseNPackets(num_packets_to_lose); | |
| 385 // Immediately after the loss, ensure at least one packet can be sent. | |
| 386 // Losses without subsequent acks can occur with timer based loss detection. | |
| 387 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 388 HAS_RETRANSMITTABLE_DATA) | |
| 389 .IsZero()); | |
| 390 AckNPackets(1); | |
| 391 | |
| 392 // We should now have fallen out of slow start with a reduced window. | |
| 393 expected_send_window *= kRenoBeta; | |
| 394 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 395 | |
| 396 // Only 2 packets should be allowed to be sent, per PRR-SSRB | |
| 397 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 398 | |
| 399 // Ack the next packet, which triggers another loss. | |
| 400 LoseNPackets(1); | |
| 401 AckNPackets(1); | |
| 402 | |
| 403 // Send 2 packets to simulate PRR-SSRB. | |
| 404 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 405 | |
| 406 // Ack the next packet, which triggers another loss. | |
| 407 LoseNPackets(1); | |
| 408 AckNPackets(1); | |
| 409 | |
| 410 // Send 2 packets to simulate PRR-SSRB. | |
| 411 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 412 | |
| 413 // Exit recovery and return to sending at the new rate. | |
| 414 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 415 AckNPackets(1); | |
| 416 EXPECT_EQ(1, SendAvailableSendWindow()); | |
| 417 } | |
| 418 } | |
| 419 | |
| 420 TEST_F(TcpCubicSenderTest, RTOCongestionWindow) { | |
| 421 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 422 EXPECT_EQ(kMaxCongestionWindow, sender_->slowstart_threshold()); | |
| 423 | |
| 424 // Expect the window to decrease to the minimum once the RTO fires | |
| 425 // and slow start threshold to be set to 1/2 of the CWND. | |
| 426 sender_->OnRetransmissionTimeout(true); | |
| 427 EXPECT_EQ(2 * kDefaultTCPMSS, sender_->GetCongestionWindow()); | |
| 428 EXPECT_EQ(5u, sender_->slowstart_threshold()); | |
| 429 } | |
| 430 | |
| 431 TEST_F(TcpCubicSenderTest, RTOCongestionWindowNoRetransmission) { | |
| 432 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 433 | |
| 434 // Expect the window to remain unchanged if the RTO fires but no | |
| 435 // packets are retransmitted. | |
| 436 sender_->OnRetransmissionTimeout(false); | |
| 437 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 438 } | |
| 439 | |
| 440 TEST_F(TcpCubicSenderTest, RetransmissionDelay) { | |
| 441 const int64_t kRttMs = 10; | |
| 442 const int64_t kDeviationMs = 3; | |
| 443 EXPECT_EQ(QuicTime::Delta::Zero(), sender_->RetransmissionDelay()); | |
| 444 | |
| 445 sender_->rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(kRttMs), | |
| 446 QuicTime::Delta::Zero(), clock_.Now()); | |
| 447 | |
| 448 // Initial value is to set the median deviation to half of the initial | |
| 449 // rtt, the median in then multiplied by a factor of 4 and finally the | |
| 450 // smoothed rtt is added which is the initial rtt. | |
| 451 QuicTime::Delta expected_delay = | |
| 452 QuicTime::Delta::FromMilliseconds(kRttMs + kRttMs / 2 * 4); | |
| 453 EXPECT_EQ(expected_delay, sender_->RetransmissionDelay()); | |
| 454 | |
| 455 for (int i = 0; i < 100; ++i) { | |
| 456 // Run to make sure that we converge. | |
| 457 sender_->rtt_stats_.UpdateRtt( | |
| 458 QuicTime::Delta::FromMilliseconds(kRttMs + kDeviationMs), | |
| 459 QuicTime::Delta::Zero(), clock_.Now()); | |
| 460 sender_->rtt_stats_.UpdateRtt( | |
| 461 QuicTime::Delta::FromMilliseconds(kRttMs - kDeviationMs), | |
| 462 QuicTime::Delta::Zero(), clock_.Now()); | |
| 463 } | |
| 464 expected_delay = QuicTime::Delta::FromMilliseconds(kRttMs + kDeviationMs * 4); | |
| 465 | |
| 466 EXPECT_NEAR(kRttMs, sender_->rtt_stats_.smoothed_rtt().ToMilliseconds(), 1); | |
| 467 EXPECT_NEAR(expected_delay.ToMilliseconds(), | |
| 468 sender_->RetransmissionDelay().ToMilliseconds(), 1); | |
| 469 EXPECT_EQ(static_cast<int64_t>( | |
| 470 sender_->GetCongestionWindow() * kNumMicrosPerSecond / | |
| 471 sender_->rtt_stats_.smoothed_rtt().ToMicroseconds()), | |
| 472 sender_->BandwidthEstimate().ToBytesPerSecond()); | |
| 473 } | |
| 474 | |
| 475 TEST_F(TcpCubicSenderTest, SlowStartMaxSendWindow) { | |
| 476 const QuicPacketCount kMaxCongestionWindowTCP = 50; | |
| 477 const int kNumberOfAcks = 100; | |
| 478 sender_.reset( | |
| 479 new TcpCubicSenderPeer(&clock_, false, kMaxCongestionWindowTCP)); | |
| 480 | |
| 481 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 482 // Send our full send window. | |
| 483 SendAvailableSendWindow(); | |
| 484 AckNPackets(2); | |
| 485 } | |
| 486 QuicByteCount expected_send_window = kMaxCongestionWindowTCP * kDefaultTCPMSS; | |
| 487 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 488 } | |
| 489 | |
| 490 TEST_F(TcpCubicSenderTest, TcpRenoMaxCongestionWindow) { | |
| 491 const QuicPacketCount kMaxCongestionWindowTCP = 50; | |
| 492 const int kNumberOfAcks = 1000; | |
| 493 sender_.reset(new TcpCubicSenderPeer(&clock_, true, kMaxCongestionWindowTCP)); | |
| 494 | |
| 495 SendAvailableSendWindow(); | |
| 496 AckNPackets(2); | |
| 497 // Make sure we fall out of slow start. | |
| 498 LoseNPackets(1); | |
| 499 | |
| 500 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 501 // Send our full send window. | |
| 502 SendAvailableSendWindow(); | |
| 503 AckNPackets(2); | |
| 504 } | |
| 505 | |
| 506 QuicByteCount expected_send_window = kMaxCongestionWindowTCP * kDefaultTCPMSS; | |
| 507 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 508 } | |
| 509 | |
| 510 TEST_F(TcpCubicSenderTest, TcpCubicMaxCongestionWindow) { | |
| 511 const QuicPacketCount kMaxCongestionWindowTCP = 50; | |
| 512 // Set to 10000 to compensate for small cubic alpha. | |
| 513 const int kNumberOfAcks = 10000; | |
| 514 | |
| 515 sender_.reset( | |
| 516 new TcpCubicSenderPeer(&clock_, false, kMaxCongestionWindowTCP)); | |
| 517 | |
| 518 SendAvailableSendWindow(); | |
| 519 AckNPackets(2); | |
| 520 // Make sure we fall out of slow start. | |
| 521 LoseNPackets(1); | |
| 522 | |
| 523 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 524 // Send our full send window. | |
| 525 SendAvailableSendWindow(); | |
| 526 AckNPackets(2); | |
| 527 } | |
| 528 | |
| 529 QuicByteCount expected_send_window = kMaxCongestionWindowTCP * kDefaultTCPMSS; | |
| 530 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 531 } | |
| 532 | |
| 533 TEST_F(TcpCubicSenderTest, TcpCubicResetEpochOnQuiescence) { | |
| 534 const int kMaxCongestionWindow = 50; | |
| 535 const QuicByteCount kMaxCongestionWindowBytes = | |
| 536 kMaxCongestionWindow * kDefaultTCPMSS; | |
| 537 sender_.reset(new TcpCubicSenderPeer(&clock_, false, kMaxCongestionWindow)); | |
| 538 | |
| 539 int num_sent = SendAvailableSendWindow(); | |
| 540 | |
| 541 // Make sure we fall out of slow start. | |
| 542 QuicByteCount saved_cwnd = sender_->GetCongestionWindow(); | |
| 543 LoseNPackets(1); | |
| 544 EXPECT_GT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 545 | |
| 546 // Ack the rest of the outstanding packets to get out of recovery. | |
| 547 for (int i = 1; i < num_sent; ++i) { | |
| 548 AckNPackets(1); | |
| 549 } | |
| 550 EXPECT_EQ(0u, bytes_in_flight_); | |
| 551 | |
| 552 // Send a new window of data and ack all; cubic growth should occur. | |
| 553 saved_cwnd = sender_->GetCongestionWindow(); | |
| 554 num_sent = SendAvailableSendWindow(); | |
| 555 for (int i = 0; i < num_sent; ++i) { | |
| 556 AckNPackets(1); | |
| 557 } | |
| 558 EXPECT_LT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 559 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 560 EXPECT_EQ(0u, bytes_in_flight_); | |
| 561 | |
| 562 // Quiescent time of 100 seconds | |
| 563 clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(100000)); | |
| 564 | |
| 565 // Send new window of data and ack one packet. Cubic epoch should have | |
| 566 // been reset; ensure cwnd increase is not dramatic. | |
| 567 saved_cwnd = sender_->GetCongestionWindow(); | |
| 568 SendAvailableSendWindow(); | |
| 569 AckNPackets(1); | |
| 570 EXPECT_NEAR(saved_cwnd, sender_->GetCongestionWindow(), kDefaultTCPMSS); | |
| 571 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 572 } | |
| 573 | |
| 574 TEST_F(TcpCubicSenderTest, TcpCubicShiftedEpochOnQuiescence) { | |
| 575 ValueRestore<bool> old_flag(&FLAGS_shift_quic_cubic_epoch_when_app_limited, | |
| 576 true); | |
| 577 const int kMaxCongestionWindow = 50; | |
| 578 const QuicByteCount kMaxCongestionWindowBytes = | |
| 579 kMaxCongestionWindow * kDefaultTCPMSS; | |
| 580 sender_.reset(new TcpCubicSenderPeer(&clock_, false, kMaxCongestionWindow)); | |
| 581 | |
| 582 int num_sent = SendAvailableSendWindow(); | |
| 583 | |
| 584 // Make sure we fall out of slow start. | |
| 585 QuicByteCount saved_cwnd = sender_->GetCongestionWindow(); | |
| 586 LoseNPackets(1); | |
| 587 EXPECT_GT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 588 | |
| 589 // Ack the rest of the outstanding packets to get out of recovery. | |
| 590 for (int i = 1; i < num_sent; ++i) { | |
| 591 AckNPackets(1); | |
| 592 } | |
| 593 EXPECT_EQ(0u, bytes_in_flight_); | |
| 594 | |
| 595 // Send a new window of data and ack all; cubic growth should occur. | |
| 596 saved_cwnd = sender_->GetCongestionWindow(); | |
| 597 num_sent = SendAvailableSendWindow(); | |
| 598 for (int i = 0; i < num_sent; ++i) { | |
| 599 AckNPackets(1); | |
| 600 } | |
| 601 EXPECT_LT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 602 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 603 EXPECT_EQ(0u, bytes_in_flight_); | |
| 604 | |
| 605 // Quiescent time of 100 seconds | |
| 606 clock_.AdvanceTime(QuicTime::Delta::FromSeconds(100)); | |
| 607 | |
| 608 // Send new window of data and ack one packet. Cubic epoch should have | |
| 609 // been reset; ensure cwnd increase is not dramatic. | |
| 610 saved_cwnd = sender_->GetCongestionWindow(); | |
| 611 SendAvailableSendWindow(); | |
| 612 AckNPackets(1); | |
| 613 EXPECT_NEAR(saved_cwnd, sender_->GetCongestionWindow(), kDefaultTCPMSS); | |
| 614 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 615 } | |
| 616 | |
| 617 TEST_F(TcpCubicSenderTest, MultipleLossesInOneWindow) { | |
| 618 SendAvailableSendWindow(); | |
| 619 const QuicByteCount initial_window = sender_->GetCongestionWindow(); | |
| 620 LosePacket(acked_packet_number_ + 1); | |
| 621 const QuicByteCount post_loss_window = sender_->GetCongestionWindow(); | |
| 622 EXPECT_GT(initial_window, post_loss_window); | |
| 623 LosePacket(acked_packet_number_ + 3); | |
| 624 EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); | |
| 625 LosePacket(packet_number_ - 1); | |
| 626 EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); | |
| 627 | |
| 628 // Lose a later packet and ensure the window decreases. | |
| 629 LosePacket(packet_number_); | |
| 630 EXPECT_GT(post_loss_window, sender_->GetCongestionWindow()); | |
| 631 } | |
| 632 | |
| 633 TEST_F(TcpCubicSenderTest, DontTrackAckPackets) { | |
| 634 // Send a packet with no retransmittable data, and ensure it's not tracked. | |
| 635 EXPECT_FALSE(sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, | |
| 636 packet_number_++, kDefaultTCPMSS, | |
| 637 NO_RETRANSMITTABLE_DATA)); | |
| 638 | |
| 639 // Send a data packet with retransmittable data, and ensure it is tracked. | |
| 640 EXPECT_TRUE(sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, | |
| 641 packet_number_++, kDefaultTCPMSS, | |
| 642 HAS_RETRANSMITTABLE_DATA)); | |
| 643 } | |
| 644 | |
| 645 TEST_F(TcpCubicSenderTest, ConfigureInitialWindow) { | |
| 646 QuicConfig config; | |
| 647 | |
| 648 QuicTagVector options; | |
| 649 options.push_back(kIW03); | |
| 650 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 651 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 652 EXPECT_EQ(3u, sender_->congestion_window()); | |
| 653 | |
| 654 options.clear(); | |
| 655 options.push_back(kIW10); | |
| 656 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 657 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 658 EXPECT_EQ(10u, sender_->congestion_window()); | |
| 659 | |
| 660 options.clear(); | |
| 661 options.push_back(kIW20); | |
| 662 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 663 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 664 EXPECT_EQ(20u, sender_->congestion_window()); | |
| 665 | |
| 666 options.clear(); | |
| 667 options.push_back(kIW50); | |
| 668 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 669 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 670 EXPECT_EQ(50u, sender_->congestion_window()); | |
| 671 } | |
| 672 | |
| 673 TEST_F(TcpCubicSenderTest, ConfigureMinimumWindow) { | |
| 674 QuicConfig config; | |
| 675 | |
| 676 // Verify that kCOPT: kMIN1 forces the min CWND to 1 packet. | |
| 677 QuicTagVector options; | |
| 678 options.push_back(kMIN1); | |
| 679 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 680 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 681 sender_->OnRetransmissionTimeout(true); | |
| 682 EXPECT_EQ(1u, sender_->congestion_window()); | |
| 683 } | |
| 684 | |
| 685 TEST_F(TcpCubicSenderTest, 2ConnectionCongestionAvoidanceAtEndOfRecovery) { | |
| 686 sender_->SetNumEmulatedConnections(2); | |
| 687 // Ack 10 packets in 5 acks to raise the CWND to 20. | |
| 688 const int kNumberOfAcks = 5; | |
| 689 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 690 // Send our full send window. | |
| 691 SendAvailableSendWindow(); | |
| 692 AckNPackets(2); | |
| 693 } | |
| 694 SendAvailableSendWindow(); | |
| 695 QuicByteCount expected_send_window = | |
| 696 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 697 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 698 | |
| 699 LoseNPackets(1); | |
| 700 | |
| 701 // We should now have fallen out of slow start with a reduced window. | |
| 702 expected_send_window = expected_send_window * sender_->GetRenoBeta(); | |
| 703 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 704 | |
| 705 // No congestion window growth should occur in recovery phase, i.e., until the | |
| 706 // currently outstanding 20 packets are acked. | |
| 707 for (int i = 0; i < 10; ++i) { | |
| 708 // Send our full send window. | |
| 709 SendAvailableSendWindow(); | |
| 710 EXPECT_TRUE(sender_->InRecovery()); | |
| 711 AckNPackets(2); | |
| 712 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 713 } | |
| 714 EXPECT_FALSE(sender_->InRecovery()); | |
| 715 | |
| 716 // Out of recovery now. Congestion window should not grow for half an RTT. | |
| 717 size_t packets_in_send_window = expected_send_window / kDefaultTCPMSS; | |
| 718 SendAvailableSendWindow(); | |
| 719 AckNPackets(packets_in_send_window / 2 - 2); | |
| 720 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 721 | |
| 722 // Next ack should increase congestion window by 1MSS. | |
| 723 SendAvailableSendWindow(); | |
| 724 AckNPackets(2); | |
| 725 expected_send_window += kDefaultTCPMSS; | |
| 726 packets_in_send_window += 1; | |
| 727 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 728 | |
| 729 // Congestion window should remain steady again for half an RTT. | |
| 730 SendAvailableSendWindow(); | |
| 731 AckNPackets(packets_in_send_window / 2 - 1); | |
| 732 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 733 | |
| 734 // Next ack should cause congestion window to grow by 1MSS. | |
| 735 SendAvailableSendWindow(); | |
| 736 AckNPackets(2); | |
| 737 expected_send_window += kDefaultTCPMSS; | |
| 738 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 739 } | |
| 740 | |
| 741 TEST_F(TcpCubicSenderTest, 1ConnectionCongestionAvoidanceAtEndOfRecovery) { | |
| 742 sender_->SetNumEmulatedConnections(1); | |
| 743 // Ack 10 packets in 5 acks to raise the CWND to 20. | |
| 744 const int kNumberOfAcks = 5; | |
| 745 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 746 // Send our full send window. | |
| 747 SendAvailableSendWindow(); | |
| 748 AckNPackets(2); | |
| 749 } | |
| 750 SendAvailableSendWindow(); | |
| 751 QuicByteCount expected_send_window = | |
| 752 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 753 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 754 | |
| 755 LoseNPackets(1); | |
| 756 | |
| 757 // We should now have fallen out of slow start with a reduced window. | |
| 758 expected_send_window *= kRenoBeta; | |
| 759 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 760 | |
| 761 // No congestion window growth should occur in recovery phase, i.e., until the | |
| 762 // currently outstanding 20 packets are acked. | |
| 763 for (int i = 0; i < 10; ++i) { | |
| 764 // Send our full send window. | |
| 765 SendAvailableSendWindow(); | |
| 766 EXPECT_TRUE(sender_->InRecovery()); | |
| 767 AckNPackets(2); | |
| 768 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 769 } | |
| 770 EXPECT_FALSE(sender_->InRecovery()); | |
| 771 | |
| 772 // Out of recovery now. Congestion window should not grow during RTT. | |
| 773 for (uint64_t i = 0; i < expected_send_window / kDefaultTCPMSS - 2; i += 2) { | |
| 774 // Send our full send window. | |
| 775 SendAvailableSendWindow(); | |
| 776 AckNPackets(2); | |
| 777 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 778 } | |
| 779 | |
| 780 // Next ack should cause congestion window to grow by 1MSS. | |
| 781 SendAvailableSendWindow(); | |
| 782 AckNPackets(2); | |
| 783 expected_send_window += kDefaultTCPMSS; | |
| 784 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 785 } | |
| 786 | |
| 787 TEST_F(TcpCubicSenderTest, BandwidthResumption) { | |
| 788 // Test that when provided with CachedNetworkParameters and opted in to the | |
| 789 // bandwidth resumption experiment, that the TcpCubicSender sets initial CWND | |
| 790 // appropriately. | |
| 791 | |
| 792 // Set some common values. | |
| 793 CachedNetworkParameters cached_network_params; | |
| 794 const QuicPacketCount kNumberOfPackets = 123; | |
| 795 const int kBandwidthEstimateBytesPerSecond = | |
| 796 kNumberOfPackets * kDefaultTCPMSS; | |
| 797 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 798 kBandwidthEstimateBytesPerSecond); | |
| 799 cached_network_params.set_min_rtt_ms(1000); | |
| 800 | |
| 801 // Make sure that a bandwidth estimate results in a changed CWND. | |
| 802 cached_network_params.set_timestamp(clock_.WallNow().ToUNIXSeconds() - | |
| 803 (kNumSecondsPerHour - 1)); | |
| 804 sender_->ResumeConnectionState(cached_network_params, false); | |
| 805 EXPECT_EQ(kNumberOfPackets, sender_->congestion_window()); | |
| 806 | |
| 807 // Resumed CWND is limited to be in a sensible range. | |
| 808 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 809 (kMaxCongestionWindow + 1) * kDefaultTCPMSS); | |
| 810 sender_->ResumeConnectionState(cached_network_params, false); | |
| 811 EXPECT_EQ(kMaxCongestionWindow, sender_->congestion_window()); | |
| 812 | |
| 813 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 814 (kMinCongestionWindowForBandwidthResumption - 1) * kDefaultTCPMSS); | |
| 815 sender_->ResumeConnectionState(cached_network_params, false); | |
| 816 EXPECT_EQ(kMinCongestionWindowForBandwidthResumption, | |
| 817 sender_->congestion_window()); | |
| 818 | |
| 819 // Resume to the max value. | |
| 820 cached_network_params.set_max_bandwidth_estimate_bytes_per_second( | |
| 821 (kMinCongestionWindowForBandwidthResumption + 10) * kDefaultTCPMSS); | |
| 822 sender_->ResumeConnectionState(cached_network_params, true); | |
| 823 EXPECT_EQ((kMinCongestionWindowForBandwidthResumption + 10) * kDefaultTCPMSS, | |
| 824 sender_->GetCongestionWindow()); | |
| 825 } | |
| 826 | |
| 827 TEST_F(TcpCubicSenderTest, PaceBelowCWND) { | |
| 828 QuicConfig config; | |
| 829 | |
| 830 // Verify that kCOPT: kMIN4 forces the min CWND to 1 packet, but allows up | |
| 831 // to 4 to be sent. | |
| 832 QuicTagVector options; | |
| 833 options.push_back(kMIN4); | |
| 834 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 835 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 836 sender_->OnRetransmissionTimeout(true); | |
| 837 EXPECT_EQ(1u, sender_->congestion_window()); | |
| 838 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), kDefaultTCPMSS, | |
| 839 HAS_RETRANSMITTABLE_DATA) | |
| 840 .IsZero()); | |
| 841 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), 2 * kDefaultTCPMSS, | |
| 842 HAS_RETRANSMITTABLE_DATA) | |
| 843 .IsZero()); | |
| 844 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), 3 * kDefaultTCPMSS, | |
| 845 HAS_RETRANSMITTABLE_DATA) | |
| 846 .IsZero()); | |
| 847 EXPECT_FALSE(sender_->TimeUntilSend(QuicTime::Zero(), 4 * kDefaultTCPMSS, | |
| 848 HAS_RETRANSMITTABLE_DATA) | |
| 849 .IsZero()); | |
| 850 } | |
| 851 | |
| 852 TEST_F(TcpCubicSenderTest, ResetAfterConnectionMigration) { | |
| 853 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 854 EXPECT_EQ(kMaxCongestionWindow, sender_->slowstart_threshold()); | |
| 855 | |
| 856 // Starts with slow start. | |
| 857 sender_->SetNumEmulatedConnections(1); | |
| 858 const int kNumberOfAcks = 10; | |
| 859 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 860 // Send our full send window. | |
| 861 SendAvailableSendWindow(); | |
| 862 AckNPackets(2); | |
| 863 } | |
| 864 SendAvailableSendWindow(); | |
| 865 QuicByteCount expected_send_window = | |
| 866 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 867 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 868 | |
| 869 // Loses a packet to exit slow start. | |
| 870 LoseNPackets(1); | |
| 871 | |
| 872 // We should now have fallen out of slow start with a reduced window. Slow | |
| 873 // start threshold is also updated. | |
| 874 expected_send_window *= kRenoBeta; | |
| 875 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 876 EXPECT_EQ(expected_send_window / kDefaultTCPMSS, | |
| 877 sender_->slowstart_threshold()); | |
| 878 | |
| 879 // Resets cwnd and slow start threshold on connection migrations. | |
| 880 sender_->OnConnectionMigration(); | |
| 881 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 882 EXPECT_EQ(kMaxCongestionWindow, sender_->slowstart_threshold()); | |
| 883 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 884 } | |
| 885 | |
| 886 } // namespace test | |
| 887 } // namespace net | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 1785663003:
Deprecate FLAG_quic_use_new_tcp_sender (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@115885351