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| 1 // Copyright (c) 2015 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_bytes_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 namespace net { | |
| 23 namespace test { | |
| 24 | |
| 25 // TODO(ianswett): A number of theses tests were written with the assumption of | |
| 26 // an initial CWND of 10. They have carefully calculated values which should be | |
| 27 // updated to be based on kInitialCongestionWindow. | |
| 28 const uint32_t kInitialCongestionWindowPackets = 10; | |
| 29 const uint32_t kDefaultWindowTCP = | |
| 30 kInitialCongestionWindowPackets * kDefaultTCPMSS; | |
| 31 const float kRenoBeta = 0.7f; // Reno backoff factor. | |
| 32 | |
| 33 class TcpCubicBytesSenderPeer : public TcpCubicBytesSender { | |
| 34 public: | |
| 35 TcpCubicBytesSenderPeer(const QuicClock* clock, bool reno) | |
| 36 : TcpCubicBytesSender(clock, | |
| 37 &rtt_stats_, | |
| 38 reno, | |
| 39 kInitialCongestionWindowPackets, | |
| 40 kMaxCongestionWindow, | |
| 41 &stats_) {} | |
| 42 | |
| 43 const HybridSlowStart& hybrid_slow_start() const { | |
| 44 return hybrid_slow_start_; | |
| 45 } | |
| 46 | |
| 47 float GetRenoBeta() const { return RenoBeta(); } | |
| 48 | |
| 49 RttStats rtt_stats_; | |
| 50 QuicConnectionStats stats_; | |
| 51 }; | |
| 52 | |
| 53 class TcpCubicBytesSenderTest : public ::testing::Test { | |
| 54 protected: | |
| 55 TcpCubicBytesSenderTest() | |
| 56 : one_ms_(QuicTime::Delta::FromMilliseconds(1)), | |
| 57 sender_(new TcpCubicBytesSenderPeer(&clock_, true)), | |
| 58 packet_number_(1), | |
| 59 acked_packet_number_(0), | |
| 60 bytes_in_flight_(0) {} | |
| 61 | |
| 62 int SendAvailableSendWindow() { | |
| 63 // Send as long as TimeUntilSend returns Zero. | |
| 64 int packets_sent = 0; | |
| 65 bool can_send = sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 66 HAS_RETRANSMITTABLE_DATA) | |
| 67 .IsZero(); | |
| 68 while (can_send) { | |
| 69 sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, packet_number_++, | |
| 70 kDefaultTCPMSS, HAS_RETRANSMITTABLE_DATA); | |
| 71 ++packets_sent; | |
| 72 bytes_in_flight_ += kDefaultTCPMSS; | |
| 73 can_send = sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 74 HAS_RETRANSMITTABLE_DATA) | |
| 75 .IsZero(); | |
| 76 } | |
| 77 return packets_sent; | |
| 78 } | |
| 79 | |
| 80 // Normal is that TCP acks every other segment. | |
| 81 void AckNPackets(int n) { | |
| 82 sender_->rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(60), | |
| 83 QuicTime::Delta::Zero(), clock_.Now()); | |
| 84 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 85 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 86 for (int i = 0; i < n; ++i) { | |
| 87 ++acked_packet_number_; | |
| 88 acked_packets.push_back( | |
| 89 std::make_pair(acked_packet_number_, kDefaultTCPMSS)); | |
| 90 } | |
| 91 sender_->OnCongestionEvent(true, bytes_in_flight_, acked_packets, | |
| 92 lost_packets); | |
| 93 bytes_in_flight_ -= n * kDefaultTCPMSS; | |
| 94 clock_.AdvanceTime(one_ms_); | |
| 95 } | |
| 96 | |
| 97 void LoseNPackets(int n) { | |
| 98 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 99 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 100 for (int i = 0; i < n; ++i) { | |
| 101 ++acked_packet_number_; | |
| 102 lost_packets.push_back( | |
| 103 std::make_pair(acked_packet_number_, kDefaultTCPMSS)); | |
| 104 } | |
| 105 sender_->OnCongestionEvent(false, bytes_in_flight_, acked_packets, | |
| 106 lost_packets); | |
| 107 bytes_in_flight_ -= n * kDefaultTCPMSS; | |
| 108 } | |
| 109 | |
| 110 // Does not increment acked_packet_number_. | |
| 111 void LosePacket(QuicPacketNumber packet_number) { | |
| 112 SendAlgorithmInterface::CongestionVector acked_packets; | |
| 113 SendAlgorithmInterface::CongestionVector lost_packets; | |
| 114 lost_packets.push_back(std::make_pair(packet_number, kDefaultTCPMSS)); | |
| 115 sender_->OnCongestionEvent(false, bytes_in_flight_, acked_packets, | |
| 116 lost_packets); | |
| 117 bytes_in_flight_ -= kDefaultTCPMSS; | |
| 118 } | |
| 119 | |
| 120 const QuicTime::Delta one_ms_; | |
| 121 MockClock clock_; | |
| 122 scoped_ptr<TcpCubicBytesSenderPeer> sender_; | |
| 123 QuicPacketNumber packet_number_; | |
| 124 QuicPacketNumber acked_packet_number_; | |
| 125 QuicByteCount bytes_in_flight_; | |
| 126 }; | |
| 127 | |
| 128 TEST_F(TcpCubicBytesSenderTest, SimpleSender) { | |
| 129 // At startup make sure we are at the default. | |
| 130 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 131 // At startup make sure we can send. | |
| 132 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 133 .IsZero()); | |
| 134 // Make sure we can send. | |
| 135 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 136 .IsZero()); | |
| 137 // And that window is un-affected. | |
| 138 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 139 | |
| 140 // Fill the send window with data, then verify that we can't send. | |
| 141 SendAvailableSendWindow(); | |
| 142 EXPECT_FALSE(sender_->TimeUntilSend(clock_.Now(), | |
| 143 sender_->GetCongestionWindow(), | |
| 144 HAS_RETRANSMITTABLE_DATA) | |
| 145 .IsZero()); | |
| 146 } | |
| 147 | |
| 148 TEST_F(TcpCubicBytesSenderTest, ApplicationLimitedSlowStart) { | |
| 149 // Send exactly 10 packets and ensure the CWND ends at 14 packets. | |
| 150 const int kNumberOfAcks = 5; | |
| 151 // At startup make sure we can send. | |
| 152 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 153 .IsZero()); | |
| 154 // Make sure we can send. | |
| 155 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 156 .IsZero()); | |
| 157 | |
| 158 SendAvailableSendWindow(); | |
| 159 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 160 AckNPackets(2); | |
| 161 } | |
| 162 QuicByteCount bytes_to_send = sender_->GetCongestionWindow(); | |
| 163 // It's expected 2 acks will arrive when the bytes_in_flight are greater than | |
| 164 // half the CWND. | |
| 165 EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * 2, bytes_to_send); | |
| 166 } | |
| 167 | |
| 168 TEST_F(TcpCubicBytesSenderTest, ExponentialSlowStart) { | |
| 169 const int kNumberOfAcks = 20; | |
| 170 // At startup make sure we can send. | |
| 171 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 172 .IsZero()); | |
| 173 EXPECT_EQ(QuicBandwidth::Zero(), sender_->BandwidthEstimate()); | |
| 174 // Make sure we can send. | |
| 175 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA) | |
| 176 .IsZero()); | |
| 177 | |
| 178 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 179 // Send our full send window. | |
| 180 SendAvailableSendWindow(); | |
| 181 AckNPackets(2); | |
| 182 } | |
| 183 const QuicByteCount cwnd = sender_->GetCongestionWindow(); | |
| 184 EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * kNumberOfAcks, cwnd); | |
| 185 EXPECT_EQ(QuicBandwidth::FromBytesAndTimeDelta( | |
| 186 cwnd, sender_->rtt_stats_.smoothed_rtt()), | |
| 187 sender_->BandwidthEstimate()); | |
| 188 } | |
| 189 | |
| 190 TEST_F(TcpCubicBytesSenderTest, SlowStartPacketLoss) { | |
| 191 sender_->SetNumEmulatedConnections(1); | |
| 192 const int kNumberOfAcks = 10; | |
| 193 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 194 // Send our full send window. | |
| 195 SendAvailableSendWindow(); | |
| 196 AckNPackets(2); | |
| 197 } | |
| 198 SendAvailableSendWindow(); | |
| 199 QuicByteCount expected_send_window = | |
| 200 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 201 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 202 | |
| 203 // Lose a packet to exit slow start. | |
| 204 LoseNPackets(1); | |
| 205 size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; | |
| 206 | |
| 207 // We should now have fallen out of slow start with a reduced window. | |
| 208 expected_send_window *= kRenoBeta; | |
| 209 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 210 | |
| 211 // Recovery phase. We need to ack every packet in the recovery window before | |
| 212 // we exit recovery. | |
| 213 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 214 DVLOG(1) << "number_packets: " << number_of_packets_in_window; | |
| 215 AckNPackets(packets_in_recovery_window); | |
| 216 SendAvailableSendWindow(); | |
| 217 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 218 | |
| 219 // We need to ack an entire window before we increase CWND by 1. | |
| 220 AckNPackets(number_of_packets_in_window - 2); | |
| 221 SendAvailableSendWindow(); | |
| 222 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 223 | |
| 224 // Next ack should increase cwnd by 1. | |
| 225 AckNPackets(1); | |
| 226 expected_send_window += kDefaultTCPMSS; | |
| 227 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 228 | |
| 229 // Now RTO and ensure slow start gets reset. | |
| 230 EXPECT_TRUE(sender_->hybrid_slow_start().started()); | |
| 231 sender_->OnRetransmissionTimeout(true); | |
| 232 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 233 } | |
| 234 | |
| 235 TEST_F(TcpCubicBytesSenderTest, SlowStartPacketLossWithLargeReduction) { | |
| 236 QuicConfig config; | |
| 237 QuicTagVector options; | |
| 238 options.push_back(kSSLR); | |
| 239 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 240 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 241 | |
| 242 sender_->SetNumEmulatedConnections(1); | |
| 243 const int kNumberOfAcks = 10; | |
| 244 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 245 // Send our full send window. | |
| 246 SendAvailableSendWindow(); | |
| 247 AckNPackets(2); | |
| 248 } | |
| 249 SendAvailableSendWindow(); | |
| 250 QuicByteCount expected_send_window = | |
| 251 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 252 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 253 | |
| 254 // Lose a packet to exit slow start. We should now have fallen out of | |
| 255 // slow start with a window reduced by 1. | |
| 256 LoseNPackets(1); | |
| 257 expected_send_window -= kDefaultTCPMSS; | |
| 258 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 259 | |
| 260 // Lose 5 packets in recovery and verify that congestion window is reduced | |
| 261 // further. | |
| 262 LoseNPackets(5); | |
| 263 expected_send_window -= 5 * kDefaultTCPMSS; | |
| 264 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 265 | |
| 266 size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; | |
| 267 | |
| 268 // Recovery phase. We need to ack every packet in the recovery window before | |
| 269 // we exit recovery. | |
| 270 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 271 DVLOG(1) << "number_packets: " << number_of_packets_in_window; | |
| 272 AckNPackets(packets_in_recovery_window); | |
| 273 SendAvailableSendWindow(); | |
| 274 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 275 | |
| 276 // We need to ack an entire window before we increase CWND by 1. | |
| 277 AckNPackets(number_of_packets_in_window - 1); | |
| 278 SendAvailableSendWindow(); | |
| 279 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 280 | |
| 281 // Next ack should increase cwnd by 1. | |
| 282 AckNPackets(1); | |
| 283 expected_send_window += kDefaultTCPMSS; | |
| 284 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 285 | |
| 286 // Now RTO and ensure slow start gets reset. | |
| 287 EXPECT_TRUE(sender_->hybrid_slow_start().started()); | |
| 288 sender_->OnRetransmissionTimeout(true); | |
| 289 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 290 } | |
| 291 | |
| 292 TEST_F(TcpCubicBytesSenderTest, NoPRRWhenLessThanOnePacketInFlight) { | |
| 293 SendAvailableSendWindow(); | |
| 294 LoseNPackets(kInitialCongestionWindowPackets - 1); | |
| 295 AckNPackets(1); | |
| 296 // PRR will allow 2 packets for every ack during recovery. | |
| 297 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 298 // Simulate abandoning all packets by supplying a bytes_in_flight of 0. | |
| 299 // PRR should now allow a packet to be sent, even though prr's state variables | |
| 300 // believe it has sent enough packets. | |
| 301 EXPECT_EQ(QuicTime::Delta::Zero(), | |
| 302 sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA)); | |
| 303 } | |
| 304 | |
| 305 TEST_F(TcpCubicBytesSenderTest, SlowStartPacketLossPRR) { | |
| 306 sender_->SetNumEmulatedConnections(1); | |
| 307 // Test based on the first example in RFC6937. | |
| 308 // Ack 10 packets in 5 acks to raise the CWND to 20, as in the example. | |
| 309 const int kNumberOfAcks = 5; | |
| 310 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 311 // Send our full send window. | |
| 312 SendAvailableSendWindow(); | |
| 313 AckNPackets(2); | |
| 314 } | |
| 315 SendAvailableSendWindow(); | |
| 316 QuicByteCount expected_send_window = | |
| 317 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 318 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 319 | |
| 320 LoseNPackets(1); | |
| 321 | |
| 322 // We should now have fallen out of slow start with a reduced window. | |
| 323 size_t send_window_before_loss = expected_send_window; | |
| 324 expected_send_window *= kRenoBeta; | |
| 325 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 326 | |
| 327 // Testing TCP proportional rate reduction. | |
| 328 // We should send packets paced over the received acks for the remaining | |
| 329 // outstanding packets. The number of packets before we exit recovery is the | |
| 330 // original CWND minus the packet that has been lost and the one which | |
| 331 // triggered the loss. | |
| 332 size_t remaining_packets_in_recovery = | |
| 333 send_window_before_loss / kDefaultTCPMSS - 2; | |
| 334 | |
| 335 for (size_t i = 0; i < remaining_packets_in_recovery; ++i) { | |
| 336 AckNPackets(1); | |
| 337 SendAvailableSendWindow(); | |
| 338 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 339 } | |
| 340 | |
| 341 // We need to ack another window before we increase CWND by 1. | |
| 342 size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; | |
| 343 for (size_t i = 0; i < number_of_packets_in_window; ++i) { | |
| 344 AckNPackets(1); | |
| 345 EXPECT_EQ(1, SendAvailableSendWindow()); | |
| 346 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 347 } | |
| 348 | |
| 349 AckNPackets(1); | |
| 350 expected_send_window += kDefaultTCPMSS; | |
| 351 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 352 } | |
| 353 | |
| 354 TEST_F(TcpCubicBytesSenderTest, SlowStartBurstPacketLossPRR) { | |
| 355 sender_->SetNumEmulatedConnections(1); | |
| 356 // Test based on the second example in RFC6937, though we also implement | |
| 357 // forward acknowledgements, so the first two incoming acks will trigger | |
| 358 // PRR immediately. | |
| 359 // Ack 20 packets in 10 acks to raise the CWND to 30. | |
| 360 const int kNumberOfAcks = 10; | |
| 361 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 362 // Send our full send window. | |
| 363 SendAvailableSendWindow(); | |
| 364 AckNPackets(2); | |
| 365 } | |
| 366 SendAvailableSendWindow(); | |
| 367 QuicByteCount expected_send_window = | |
| 368 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 369 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 370 | |
| 371 // Lose one more than the congestion window reduction, so that after loss, | |
| 372 // bytes_in_flight is lesser than the congestion window. | |
| 373 size_t send_window_after_loss = kRenoBeta * expected_send_window; | |
| 374 size_t num_packets_to_lose = | |
| 375 (expected_send_window - send_window_after_loss) / kDefaultTCPMSS + 1; | |
| 376 LoseNPackets(num_packets_to_lose); | |
| 377 // Immediately after the loss, ensure at least one packet can be sent. | |
| 378 // Losses without subsequent acks can occur with timer based loss detection. | |
| 379 EXPECT_TRUE(sender_->TimeUntilSend(clock_.Now(), bytes_in_flight_, | |
| 380 HAS_RETRANSMITTABLE_DATA) | |
| 381 .IsZero()); | |
| 382 AckNPackets(1); | |
| 383 | |
| 384 // We should now have fallen out of slow start with a reduced window. | |
| 385 expected_send_window *= kRenoBeta; | |
| 386 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 387 | |
| 388 // Only 2 packets should be allowed to be sent, per PRR-SSRB. | |
| 389 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 390 | |
| 391 // Ack the next packet, which triggers another loss. | |
| 392 LoseNPackets(1); | |
| 393 AckNPackets(1); | |
| 394 | |
| 395 // Send 2 packets to simulate PRR-SSRB. | |
| 396 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 397 | |
| 398 // Ack the next packet, which triggers another loss. | |
| 399 LoseNPackets(1); | |
| 400 AckNPackets(1); | |
| 401 | |
| 402 // Send 2 packets to simulate PRR-SSRB. | |
| 403 EXPECT_EQ(2, SendAvailableSendWindow()); | |
| 404 | |
| 405 // Exit recovery and return to sending at the new rate. | |
| 406 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 407 AckNPackets(1); | |
| 408 EXPECT_EQ(1, SendAvailableSendWindow()); | |
| 409 } | |
| 410 } | |
| 411 | |
| 412 TEST_F(TcpCubicBytesSenderTest, RTOCongestionWindow) { | |
| 413 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 414 // Expect the window to decrease to the minimum once the RTO fires and slow | |
| 415 // start threshold to be set to 1/2 of the CWND. | |
| 416 sender_->OnRetransmissionTimeout(true); | |
| 417 EXPECT_EQ(2 * kDefaultTCPMSS, sender_->GetCongestionWindow()); | |
| 418 EXPECT_EQ(5u * kDefaultTCPMSS, sender_->GetSlowStartThreshold()); | |
| 419 } | |
| 420 | |
| 421 TEST_F(TcpCubicBytesSenderTest, RTOCongestionWindowNoRetransmission) { | |
| 422 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 423 | |
| 424 // Expect the window to remain unchanged if the RTO fires but no packets are | |
| 425 // retransmitted. | |
| 426 sender_->OnRetransmissionTimeout(false); | |
| 427 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 428 } | |
| 429 | |
| 430 TEST_F(TcpCubicBytesSenderTest, RetransmissionDelay) { | |
| 431 const int64_t kRttMs = 10; | |
| 432 const int64_t kDeviationMs = 3; | |
| 433 EXPECT_EQ(QuicTime::Delta::Zero(), sender_->RetransmissionDelay()); | |
| 434 | |
| 435 sender_->rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(kRttMs), | |
| 436 QuicTime::Delta::Zero(), clock_.Now()); | |
| 437 | |
| 438 // Initial value is to set the median deviation to half of the initial rtt, | |
| 439 // the median in then multiplied by a factor of 4 and finally the smoothed rtt | |
| 440 // is added which is the initial rtt. | |
| 441 QuicTime::Delta expected_delay = | |
| 442 QuicTime::Delta::FromMilliseconds(kRttMs + kRttMs / 2 * 4); | |
| 443 EXPECT_EQ(expected_delay, sender_->RetransmissionDelay()); | |
| 444 | |
| 445 for (int i = 0; i < 100; ++i) { | |
| 446 // Run to make sure that we converge. | |
| 447 sender_->rtt_stats_.UpdateRtt( | |
| 448 QuicTime::Delta::FromMilliseconds(kRttMs + kDeviationMs), | |
| 449 QuicTime::Delta::Zero(), clock_.Now()); | |
| 450 sender_->rtt_stats_.UpdateRtt( | |
| 451 QuicTime::Delta::FromMilliseconds(kRttMs - kDeviationMs), | |
| 452 QuicTime::Delta::Zero(), clock_.Now()); | |
| 453 } | |
| 454 expected_delay = QuicTime::Delta::FromMilliseconds(kRttMs + kDeviationMs * 4); | |
| 455 | |
| 456 EXPECT_NEAR(kRttMs, sender_->rtt_stats_.smoothed_rtt().ToMilliseconds(), 1); | |
| 457 EXPECT_NEAR(expected_delay.ToMilliseconds(), | |
| 458 sender_->RetransmissionDelay().ToMilliseconds(), 1); | |
| 459 EXPECT_EQ(static_cast<int64_t>( | |
| 460 sender_->GetCongestionWindow() * kNumMicrosPerSecond / | |
| 461 sender_->rtt_stats_.smoothed_rtt().ToMicroseconds()), | |
| 462 sender_->BandwidthEstimate().ToBytesPerSecond()); | |
| 463 } | |
| 464 | |
| 465 TEST_F(TcpCubicBytesSenderTest, TcpCubicResetEpochOnQuiescence) { | |
| 466 const int kMaxCongestionWindow = 50; | |
| 467 const QuicByteCount kMaxCongestionWindowBytes = | |
| 468 kMaxCongestionWindow * kDefaultTCPMSS; | |
| 469 int num_sent = SendAvailableSendWindow(); | |
| 470 | |
| 471 // Make sure we fall out of slow start. | |
| 472 QuicByteCount saved_cwnd = sender_->GetCongestionWindow(); | |
| 473 LoseNPackets(1); | |
| 474 EXPECT_GT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 475 | |
| 476 // Ack the rest of the outstanding packets to get out of recovery. | |
| 477 for (int i = 1; i < num_sent; ++i) { | |
| 478 AckNPackets(1); | |
| 479 } | |
| 480 EXPECT_EQ(0u, bytes_in_flight_); | |
| 481 | |
| 482 // Send a new window of data and ack all; cubic growth should occur. | |
| 483 saved_cwnd = sender_->GetCongestionWindow(); | |
| 484 num_sent = SendAvailableSendWindow(); | |
| 485 for (int i = 0; i < num_sent; ++i) { | |
| 486 AckNPackets(1); | |
| 487 } | |
| 488 EXPECT_LT(saved_cwnd, sender_->GetCongestionWindow()); | |
| 489 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 490 EXPECT_EQ(0u, bytes_in_flight_); | |
| 491 | |
| 492 // Quiescent time of 100 seconds | |
| 493 clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(100000)); | |
| 494 | |
| 495 // Send new window of data and ack one packet. Cubic epoch should have | |
| 496 // been reset; ensure cwnd increase is not dramatic. | |
| 497 saved_cwnd = sender_->GetCongestionWindow(); | |
| 498 SendAvailableSendWindow(); | |
| 499 AckNPackets(1); | |
| 500 EXPECT_NEAR(saved_cwnd, sender_->GetCongestionWindow(), kDefaultTCPMSS); | |
| 501 EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); | |
| 502 } | |
| 503 | |
| 504 TEST_F(TcpCubicBytesSenderTest, MultipleLossesInOneWindow) { | |
| 505 SendAvailableSendWindow(); | |
| 506 const QuicByteCount initial_window = sender_->GetCongestionWindow(); | |
| 507 LosePacket(acked_packet_number_ + 1); | |
| 508 const QuicByteCount post_loss_window = sender_->GetCongestionWindow(); | |
| 509 EXPECT_GT(initial_window, post_loss_window); | |
| 510 LosePacket(acked_packet_number_ + 3); | |
| 511 EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); | |
| 512 LosePacket(packet_number_ - 1); | |
| 513 EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); | |
| 514 | |
| 515 // Lose a later packet and ensure the window decreases. | |
| 516 LosePacket(packet_number_); | |
| 517 EXPECT_GT(post_loss_window, sender_->GetCongestionWindow()); | |
| 518 } | |
| 519 | |
| 520 TEST_F(TcpCubicBytesSenderTest, DontTrackAckPackets) { | |
| 521 // Send a packet with no retransmittable data, and ensure it's not tracked. | |
| 522 EXPECT_FALSE(sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, | |
| 523 packet_number_++, kDefaultTCPMSS, | |
| 524 NO_RETRANSMITTABLE_DATA)); | |
| 525 | |
| 526 // Send a data packet with retransmittable data, and ensure it is tracked. | |
| 527 EXPECT_TRUE(sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, | |
| 528 packet_number_++, kDefaultTCPMSS, | |
| 529 HAS_RETRANSMITTABLE_DATA)); | |
| 530 } | |
| 531 | |
| 532 TEST_F(TcpCubicBytesSenderTest, ConfigureMaxInitialWindow) { | |
| 533 QuicConfig config; | |
| 534 | |
| 535 // Verify that kCOPT: kIW10 forces the congestion window to the default of 10. | |
| 536 QuicTagVector options; | |
| 537 options.push_back(kIW10); | |
| 538 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 539 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 540 EXPECT_EQ(10u * kDefaultTCPMSS, sender_->GetCongestionWindow()); | |
| 541 } | |
| 542 | |
| 543 TEST_F(TcpCubicBytesSenderTest, 2ConnectionCongestionAvoidanceAtEndOfRecovery) { | |
| 544 sender_->SetNumEmulatedConnections(2); | |
| 545 // Ack 10 packets in 5 acks to raise the CWND to 20. | |
| 546 const int kNumberOfAcks = 5; | |
| 547 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 548 // Send our full send window. | |
| 549 SendAvailableSendWindow(); | |
| 550 AckNPackets(2); | |
| 551 } | |
| 552 SendAvailableSendWindow(); | |
| 553 QuicByteCount expected_send_window = | |
| 554 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 555 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 556 | |
| 557 LoseNPackets(1); | |
| 558 | |
| 559 // We should now have fallen out of slow start with a reduced window. | |
| 560 expected_send_window = expected_send_window * sender_->GetRenoBeta(); | |
| 561 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 562 | |
| 563 // No congestion window growth should occur in recovery phase, i.e., until the | |
| 564 // currently outstanding 20 packets are acked. | |
| 565 for (int i = 0; i < 10; ++i) { | |
| 566 // Send our full send window. | |
| 567 SendAvailableSendWindow(); | |
| 568 EXPECT_TRUE(sender_->InRecovery()); | |
| 569 AckNPackets(2); | |
| 570 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 571 } | |
| 572 EXPECT_FALSE(sender_->InRecovery()); | |
| 573 | |
| 574 // Out of recovery now. Congestion window should not grow for half an RTT. | |
| 575 size_t packets_in_send_window = expected_send_window / kDefaultTCPMSS; | |
| 576 SendAvailableSendWindow(); | |
| 577 AckNPackets(packets_in_send_window / 2 - 2); | |
| 578 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 579 | |
| 580 // Next ack should increase congestion window by 1MSS. | |
| 581 SendAvailableSendWindow(); | |
| 582 AckNPackets(2); | |
| 583 expected_send_window += kDefaultTCPMSS; | |
| 584 packets_in_send_window += 1; | |
| 585 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 586 | |
| 587 // Congestion window should remain steady again for half an RTT. | |
| 588 SendAvailableSendWindow(); | |
| 589 AckNPackets(packets_in_send_window / 2 - 1); | |
| 590 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 591 | |
| 592 // Next ack should cause congestion window to grow by 1MSS. | |
| 593 SendAvailableSendWindow(); | |
| 594 AckNPackets(2); | |
| 595 expected_send_window += kDefaultTCPMSS; | |
| 596 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 597 } | |
| 598 | |
| 599 TEST_F(TcpCubicBytesSenderTest, 1ConnectionCongestionAvoidanceAtEndOfRecovery) { | |
| 600 sender_->SetNumEmulatedConnections(1); | |
| 601 // Ack 10 packets in 5 acks to raise the CWND to 20. | |
| 602 const int kNumberOfAcks = 5; | |
| 603 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 604 // Send our full send window. | |
| 605 SendAvailableSendWindow(); | |
| 606 AckNPackets(2); | |
| 607 } | |
| 608 SendAvailableSendWindow(); | |
| 609 QuicByteCount expected_send_window = | |
| 610 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 611 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 612 | |
| 613 LoseNPackets(1); | |
| 614 | |
| 615 // We should now have fallen out of slow start with a reduced window. | |
| 616 expected_send_window *= kRenoBeta; | |
| 617 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 618 | |
| 619 // No congestion window growth should occur in recovery phase, i.e., until the | |
| 620 // currently outstanding 20 packets are acked. | |
| 621 for (int i = 0; i < 10; ++i) { | |
| 622 // Send our full send window. | |
| 623 SendAvailableSendWindow(); | |
| 624 EXPECT_TRUE(sender_->InRecovery()); | |
| 625 AckNPackets(2); | |
| 626 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 627 } | |
| 628 EXPECT_FALSE(sender_->InRecovery()); | |
| 629 | |
| 630 // Out of recovery now. Congestion window should not grow during RTT. | |
| 631 for (uint64_t i = 0; i < expected_send_window / kDefaultTCPMSS - 2; i += 2) { | |
| 632 // Send our full send window. | |
| 633 SendAvailableSendWindow(); | |
| 634 AckNPackets(2); | |
| 635 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 636 } | |
| 637 | |
| 638 // Next ack should cause congestion window to grow by 1MSS. | |
| 639 SendAvailableSendWindow(); | |
| 640 AckNPackets(2); | |
| 641 expected_send_window += kDefaultTCPMSS; | |
| 642 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 643 } | |
| 644 | |
| 645 TEST_F(TcpCubicBytesSenderTest, BandwidthResumption) { | |
| 646 // Test that when provided with CachedNetworkParameters and opted in to the | |
| 647 // bandwidth resumption experiment, that the TcpCubicSender sets initial CWND | |
| 648 // appropriately. | |
| 649 | |
| 650 // Set some common values. | |
| 651 CachedNetworkParameters cached_network_params; | |
| 652 const QuicPacketCount kNumberOfPackets = 123; | |
| 653 const int kBandwidthEstimateBytesPerSecond = | |
| 654 kNumberOfPackets * kDefaultTCPMSS; | |
| 655 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 656 kBandwidthEstimateBytesPerSecond); | |
| 657 cached_network_params.set_min_rtt_ms(1000); | |
| 658 | |
| 659 // Make sure that a bandwidth estimate results in a changed CWND. | |
| 660 cached_network_params.set_timestamp(clock_.WallNow().ToUNIXSeconds() - | |
| 661 (kNumSecondsPerHour - 1)); | |
| 662 sender_->ResumeConnectionState(cached_network_params, false); | |
| 663 EXPECT_EQ(kNumberOfPackets * kDefaultTCPMSS, sender_->GetCongestionWindow()); | |
| 664 | |
| 665 // Resumed CWND is limited to be in a sensible range. | |
| 666 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 667 (kMaxCongestionWindow + 1) * kDefaultTCPMSS); | |
| 668 sender_->ResumeConnectionState(cached_network_params, false); | |
| 669 EXPECT_EQ(kMaxCongestionWindow * kDefaultTCPMSS, | |
| 670 sender_->GetCongestionWindow()); | |
| 671 | |
| 672 cached_network_params.set_bandwidth_estimate_bytes_per_second( | |
| 673 (kMinCongestionWindowForBandwidthResumption - 1) * kDefaultTCPMSS); | |
| 674 sender_->ResumeConnectionState(cached_network_params, false); | |
| 675 EXPECT_EQ(kMinCongestionWindowForBandwidthResumption * kDefaultTCPMSS, | |
| 676 sender_->GetCongestionWindow()); | |
| 677 | |
| 678 // Resume to the max value. | |
| 679 cached_network_params.set_max_bandwidth_estimate_bytes_per_second( | |
| 680 (kMinCongestionWindowForBandwidthResumption + 10) * kDefaultTCPMSS); | |
| 681 sender_->ResumeConnectionState(cached_network_params, true); | |
| 682 EXPECT_EQ((kMinCongestionWindowForBandwidthResumption + 10) * kDefaultTCPMSS, | |
| 683 sender_->GetCongestionWindow()); | |
| 684 } | |
| 685 | |
| 686 TEST_F(TcpCubicBytesSenderTest, PaceBelowCWND) { | |
| 687 QuicConfig config; | |
| 688 | |
| 689 // Verify that kCOPT: kMIN4 forces the min CWND to 1 packet, but allows up | |
| 690 // to 4 to be sent. | |
| 691 QuicTagVector options; | |
| 692 options.push_back(kMIN4); | |
| 693 QuicConfigPeer::SetReceivedConnectionOptions(&config, options); | |
| 694 sender_->SetFromConfig(config, Perspective::IS_SERVER); | |
| 695 sender_->OnRetransmissionTimeout(true); | |
| 696 EXPECT_EQ(kDefaultTCPMSS, sender_->GetCongestionWindow()); | |
| 697 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), kDefaultTCPMSS, | |
| 698 HAS_RETRANSMITTABLE_DATA) | |
| 699 .IsZero()); | |
| 700 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), 2 * kDefaultTCPMSS, | |
| 701 HAS_RETRANSMITTABLE_DATA) | |
| 702 .IsZero()); | |
| 703 EXPECT_TRUE(sender_->TimeUntilSend(QuicTime::Zero(), 3 * kDefaultTCPMSS, | |
| 704 HAS_RETRANSMITTABLE_DATA) | |
| 705 .IsZero()); | |
| 706 EXPECT_FALSE(sender_->TimeUntilSend(QuicTime::Zero(), 4 * kDefaultTCPMSS, | |
| 707 HAS_RETRANSMITTABLE_DATA) | |
| 708 .IsZero()); | |
| 709 } | |
| 710 | |
| 711 TEST_F(TcpCubicBytesSenderTest, ResetAfterConnectionMigration) { | |
| 712 // Starts from slow start. | |
| 713 sender_->SetNumEmulatedConnections(1); | |
| 714 const int kNumberOfAcks = 10; | |
| 715 for (int i = 0; i < kNumberOfAcks; ++i) { | |
| 716 // Send our full send window. | |
| 717 SendAvailableSendWindow(); | |
| 718 AckNPackets(2); | |
| 719 } | |
| 720 SendAvailableSendWindow(); | |
| 721 QuicByteCount expected_send_window = | |
| 722 kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); | |
| 723 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 724 | |
| 725 // Loses a packet to exit slow start. | |
| 726 LoseNPackets(1); | |
| 727 | |
| 728 // We should now have fallen out of slow start with a reduced window. Slow | |
| 729 // start threshold is also updated. | |
| 730 expected_send_window *= kRenoBeta; | |
| 731 EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); | |
| 732 EXPECT_EQ(expected_send_window, sender_->GetSlowStartThreshold()); | |
| 733 | |
| 734 // Resets cwnd and slow start threshold on connection migrations. | |
| 735 sender_->OnConnectionMigration(); | |
| 736 EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); | |
| 737 EXPECT_EQ(kMaxCongestionWindow * kDefaultTCPMSS, | |
| 738 sender_->GetSlowStartThreshold()); | |
| 739 EXPECT_FALSE(sender_->hybrid_slow_start().started()); | |
| 740 } | |
| 741 | |
| 742 } // namespace test | |
| 743 } // 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