| // Copyright (c) 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 "quiche/quic/core/congestion_control/tcp_cubic_sender_bytes.h" |
| |
| #include <algorithm> |
| #include <cstdint> |
| #include <memory> |
| #include <utility> |
| |
| #include "quiche/quic/core/congestion_control/rtt_stats.h" |
| #include "quiche/quic/core/congestion_control/send_algorithm_interface.h" |
| #include "quiche/quic/core/crypto/crypto_protocol.h" |
| #include "quiche/quic/core/quic_packets.h" |
| #include "quiche/quic/core/quic_utils.h" |
| #include "quiche/quic/platform/api/quic_logging.h" |
| #include "quiche/quic/platform/api/quic_test.h" |
| #include "quiche/quic/test_tools/mock_clock.h" |
| #include "quiche/quic/test_tools/quic_config_peer.h" |
| |
| namespace quic { |
| namespace test { |
| |
| // TODO(ianswett): A number of theses tests were written with the assumption of |
| // an initial CWND of 10. They have carefully calculated values which should be |
| // updated to be based on kInitialCongestionWindow. |
| const uint32_t kInitialCongestionWindowPackets = 10; |
| const uint32_t kMaxCongestionWindowPackets = 200; |
| const uint32_t kDefaultWindowTCP = |
| kInitialCongestionWindowPackets * kDefaultTCPMSS; |
| const float kRenoBeta = 0.7f; // Reno backoff factor. |
| |
| class TcpCubicSenderBytesPeer : public TcpCubicSenderBytes { |
| public: |
| TcpCubicSenderBytesPeer(const QuicClock* clock, bool reno) |
| : TcpCubicSenderBytes(clock, &rtt_stats_, reno, |
| kInitialCongestionWindowPackets, |
| kMaxCongestionWindowPackets, &stats_) {} |
| |
| const HybridSlowStart& hybrid_slow_start() const { |
| return hybrid_slow_start_; |
| } |
| |
| float GetRenoBeta() const { return RenoBeta(); } |
| |
| RttStats rtt_stats_; |
| QuicConnectionStats stats_; |
| }; |
| |
| class TcpCubicSenderBytesTest : public QuicTest { |
| protected: |
| TcpCubicSenderBytesTest() |
| : one_ms_(QuicTime::Delta::FromMilliseconds(1)), |
| sender_(new TcpCubicSenderBytesPeer(&clock_, true)), |
| packet_number_(1), |
| acked_packet_number_(0), |
| bytes_in_flight_(0) {} |
| |
| int SendAvailableSendWindow() { |
| return SendAvailableSendWindow(kDefaultTCPMSS); |
| } |
| |
| int SendAvailableSendWindow(QuicPacketLength /*packet_length*/) { |
| // Send as long as TimeUntilSend returns Zero. |
| int packets_sent = 0; |
| bool can_send = sender_->CanSend(bytes_in_flight_); |
| while (can_send) { |
| sender_->OnPacketSent(clock_.Now(), bytes_in_flight_, |
| QuicPacketNumber(packet_number_++), kDefaultTCPMSS, |
| HAS_RETRANSMITTABLE_DATA); |
| ++packets_sent; |
| bytes_in_flight_ += kDefaultTCPMSS; |
| can_send = sender_->CanSend(bytes_in_flight_); |
| } |
| return packets_sent; |
| } |
| |
| // Normal is that TCP acks every other segment. |
| void AckNPackets(int n) { |
| sender_->rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(60), |
| QuicTime::Delta::Zero(), clock_.Now()); |
| AckedPacketVector acked_packets; |
| LostPacketVector lost_packets; |
| for (int i = 0; i < n; ++i) { |
| ++acked_packet_number_; |
| acked_packets.push_back( |
| AckedPacket(QuicPacketNumber(acked_packet_number_), kDefaultTCPMSS, |
| QuicTime::Zero())); |
| } |
| sender_->OnCongestionEvent(true, bytes_in_flight_, clock_.Now(), |
| acked_packets, lost_packets); |
| bytes_in_flight_ -= n * kDefaultTCPMSS; |
| clock_.AdvanceTime(one_ms_); |
| } |
| |
| void LoseNPackets(int n) { LoseNPackets(n, kDefaultTCPMSS); } |
| |
| void LoseNPackets(int n, QuicPacketLength packet_length) { |
| AckedPacketVector acked_packets; |
| LostPacketVector lost_packets; |
| for (int i = 0; i < n; ++i) { |
| ++acked_packet_number_; |
| lost_packets.push_back( |
| LostPacket(QuicPacketNumber(acked_packet_number_), packet_length)); |
| } |
| sender_->OnCongestionEvent(false, bytes_in_flight_, clock_.Now(), |
| acked_packets, lost_packets); |
| bytes_in_flight_ -= n * packet_length; |
| } |
| |
| // Does not increment acked_packet_number_. |
| void LosePacket(uint64_t packet_number) { |
| AckedPacketVector acked_packets; |
| LostPacketVector lost_packets; |
| lost_packets.push_back( |
| LostPacket(QuicPacketNumber(packet_number), kDefaultTCPMSS)); |
| sender_->OnCongestionEvent(false, bytes_in_flight_, clock_.Now(), |
| acked_packets, lost_packets); |
| bytes_in_flight_ -= kDefaultTCPMSS; |
| } |
| |
| const QuicTime::Delta one_ms_; |
| MockClock clock_; |
| std::unique_ptr<TcpCubicSenderBytesPeer> sender_; |
| uint64_t packet_number_; |
| uint64_t acked_packet_number_; |
| QuicByteCount bytes_in_flight_; |
| }; |
| |
| TEST_F(TcpCubicSenderBytesTest, SimpleSender) { |
| // At startup make sure we are at the default. |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| // At startup make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| // Make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| // And that window is un-affected. |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| |
| // Fill the send window with data, then verify that we can't send. |
| SendAvailableSendWindow(); |
| EXPECT_FALSE(sender_->CanSend(sender_->GetCongestionWindow())); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, ApplicationLimitedSlowStart) { |
| // Send exactly 10 packets and ensure the CWND ends at 14 packets. |
| const int kNumberOfAcks = 5; |
| // At startup make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| // Make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| |
| SendAvailableSendWindow(); |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| AckNPackets(2); |
| } |
| QuicByteCount bytes_to_send = sender_->GetCongestionWindow(); |
| // It's expected 2 acks will arrive when the bytes_in_flight are greater than |
| // half the CWND. |
| EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * 2, bytes_to_send); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, ExponentialSlowStart) { |
| const int kNumberOfAcks = 20; |
| // At startup make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| EXPECT_EQ(QuicBandwidth::Zero(), sender_->BandwidthEstimate()); |
| // Make sure we can send. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| const QuicByteCount cwnd = sender_->GetCongestionWindow(); |
| EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * kNumberOfAcks, cwnd); |
| EXPECT_EQ(QuicBandwidth::FromBytesAndTimeDelta( |
| cwnd, sender_->rtt_stats_.smoothed_rtt()), |
| sender_->BandwidthEstimate()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartPacketLoss) { |
| sender_->SetNumEmulatedConnections(1); |
| const int kNumberOfAcks = 10; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose a packet to exit slow start. |
| LoseNPackets(1); |
| size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; |
| |
| // We should now have fallen out of slow start with a reduced window. |
| expected_send_window *= kRenoBeta; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Recovery phase. We need to ack every packet in the recovery window before |
| // we exit recovery. |
| size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; |
| QUIC_DLOG(INFO) << "number_packets: " << number_of_packets_in_window; |
| AckNPackets(packets_in_recovery_window); |
| SendAvailableSendWindow(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // We need to ack an entire window before we increase CWND by 1. |
| AckNPackets(number_of_packets_in_window - 2); |
| SendAvailableSendWindow(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Next ack should increase cwnd by 1. |
| AckNPackets(1); |
| expected_send_window += kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Now RTO and ensure slow start gets reset. |
| EXPECT_TRUE(sender_->hybrid_slow_start().started()); |
| sender_->OnRetransmissionTimeout(true); |
| EXPECT_FALSE(sender_->hybrid_slow_start().started()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartPacketLossWithLargeReduction) { |
| QuicConfig config; |
| QuicTagVector options; |
| options.push_back(kSSLR); |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| |
| sender_->SetNumEmulatedConnections(1); |
| const int kNumberOfAcks = (kDefaultWindowTCP / (2 * kDefaultTCPMSS)) - 1; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose a packet to exit slow start. We should now have fallen out of |
| // slow start with a window reduced by 1. |
| LoseNPackets(1); |
| expected_send_window -= kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose 5 packets in recovery and verify that congestion window is reduced |
| // further. |
| LoseNPackets(5); |
| expected_send_window -= 5 * kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| // Lose another 10 packets and ensure it reduces below half the peak CWND, |
| // because we never acked the full IW. |
| LoseNPackets(10); |
| expected_send_window -= 10 * kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| size_t packets_in_recovery_window = expected_send_window / kDefaultTCPMSS; |
| |
| // Recovery phase. We need to ack every packet in the recovery window before |
| // we exit recovery. |
| size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; |
| QUIC_DLOG(INFO) << "number_packets: " << number_of_packets_in_window; |
| AckNPackets(packets_in_recovery_window); |
| SendAvailableSendWindow(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // We need to ack an entire window before we increase CWND by 1. |
| AckNPackets(number_of_packets_in_window - 1); |
| SendAvailableSendWindow(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Next ack should increase cwnd by 1. |
| AckNPackets(1); |
| expected_send_window += kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Now RTO and ensure slow start gets reset. |
| EXPECT_TRUE(sender_->hybrid_slow_start().started()); |
| sender_->OnRetransmissionTimeout(true); |
| EXPECT_FALSE(sender_->hybrid_slow_start().started()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartHalfPacketLossWithLargeReduction) { |
| QuicConfig config; |
| QuicTagVector options; |
| options.push_back(kSSLR); |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| |
| sender_->SetNumEmulatedConnections(1); |
| const int kNumberOfAcks = 10; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window in half sized packets. |
| SendAvailableSendWindow(kDefaultTCPMSS / 2); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(kDefaultTCPMSS / 2); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose a packet to exit slow start. We should now have fallen out of |
| // slow start with a window reduced by 1. |
| LoseNPackets(1); |
| expected_send_window -= kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose 10 packets in recovery and verify that congestion window is reduced |
| // by 5 packets. |
| LoseNPackets(10, kDefaultTCPMSS / 2); |
| expected_send_window -= 5 * kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartPacketLossWithMaxHalfReduction) { |
| QuicConfig config; |
| QuicTagVector options; |
| options.push_back(kSSLR); |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| |
| sender_->SetNumEmulatedConnections(1); |
| const int kNumberOfAcks = kInitialCongestionWindowPackets / 2; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose a packet to exit slow start. We should now have fallen out of |
| // slow start with a window reduced by 1. |
| LoseNPackets(1); |
| expected_send_window -= kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose half the outstanding packets in recovery and verify the congestion |
| // window is only reduced by a max of half. |
| LoseNPackets(kNumberOfAcks * 2); |
| expected_send_window -= (kNumberOfAcks * 2 - 1) * kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| LoseNPackets(5); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, NoPRRWhenLessThanOnePacketInFlight) { |
| SendAvailableSendWindow(); |
| LoseNPackets(kInitialCongestionWindowPackets - 1); |
| AckNPackets(1); |
| // PRR will allow 2 packets for every ack during recovery. |
| EXPECT_EQ(2, SendAvailableSendWindow()); |
| // Simulate abandoning all packets by supplying a bytes_in_flight of 0. |
| // PRR should now allow a packet to be sent, even though prr's state variables |
| // believe it has sent enough packets. |
| EXPECT_TRUE(sender_->CanSend(0)); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartPacketLossPRR) { |
| sender_->SetNumEmulatedConnections(1); |
| // Test based on the first example in RFC6937. |
| // Ack 10 packets in 5 acks to raise the CWND to 20, as in the example. |
| const int kNumberOfAcks = 5; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| LoseNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. |
| size_t send_window_before_loss = expected_send_window; |
| expected_send_window *= kRenoBeta; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Testing TCP proportional rate reduction. |
| // We should send packets paced over the received acks for the remaining |
| // outstanding packets. The number of packets before we exit recovery is the |
| // original CWND minus the packet that has been lost and the one which |
| // triggered the loss. |
| size_t remaining_packets_in_recovery = |
| send_window_before_loss / kDefaultTCPMSS - 2; |
| |
| for (size_t i = 0; i < remaining_packets_in_recovery; ++i) { |
| AckNPackets(1); |
| SendAvailableSendWindow(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| // We need to ack another window before we increase CWND by 1. |
| size_t number_of_packets_in_window = expected_send_window / kDefaultTCPMSS; |
| for (size_t i = 0; i < number_of_packets_in_window; ++i) { |
| AckNPackets(1); |
| EXPECT_EQ(1, SendAvailableSendWindow()); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| AckNPackets(1); |
| expected_send_window += kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SlowStartBurstPacketLossPRR) { |
| sender_->SetNumEmulatedConnections(1); |
| // Test based on the second example in RFC6937, though we also implement |
| // forward acknowledgements, so the first two incoming acks will trigger |
| // PRR immediately. |
| // Ack 20 packets in 10 acks to raise the CWND to 30. |
| const int kNumberOfAcks = 10; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Lose one more than the congestion window reduction, so that after loss, |
| // bytes_in_flight is lesser than the congestion window. |
| size_t send_window_after_loss = kRenoBeta * expected_send_window; |
| size_t num_packets_to_lose = |
| (expected_send_window - send_window_after_loss) / kDefaultTCPMSS + 1; |
| LoseNPackets(num_packets_to_lose); |
| // Immediately after the loss, ensure at least one packet can be sent. |
| // Losses without subsequent acks can occur with timer based loss detection. |
| EXPECT_TRUE(sender_->CanSend(bytes_in_flight_)); |
| AckNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. |
| expected_send_window *= kRenoBeta; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Only 2 packets should be allowed to be sent, per PRR-SSRB. |
| EXPECT_EQ(2, SendAvailableSendWindow()); |
| |
| // Ack the next packet, which triggers another loss. |
| LoseNPackets(1); |
| AckNPackets(1); |
| |
| // Send 2 packets to simulate PRR-SSRB. |
| EXPECT_EQ(2, SendAvailableSendWindow()); |
| |
| // Ack the next packet, which triggers another loss. |
| LoseNPackets(1); |
| AckNPackets(1); |
| |
| // Send 2 packets to simulate PRR-SSRB. |
| EXPECT_EQ(2, SendAvailableSendWindow()); |
| |
| // Exit recovery and return to sending at the new rate. |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| AckNPackets(1); |
| EXPECT_EQ(1, SendAvailableSendWindow()); |
| } |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, RTOCongestionWindow) { |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| // Expect the window to decrease to the minimum once the RTO fires and slow |
| // start threshold to be set to 1/2 of the CWND. |
| sender_->OnRetransmissionTimeout(true); |
| EXPECT_EQ(2 * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| EXPECT_EQ(5u * kDefaultTCPMSS, sender_->GetSlowStartThreshold()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, RTOCongestionWindowNoRetransmission) { |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| |
| // Expect the window to remain unchanged if the RTO fires but no packets are |
| // retransmitted. |
| sender_->OnRetransmissionTimeout(false); |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, TcpCubicResetEpochOnQuiescence) { |
| const int kMaxCongestionWindow = 50; |
| const QuicByteCount kMaxCongestionWindowBytes = |
| kMaxCongestionWindow * kDefaultTCPMSS; |
| int num_sent = SendAvailableSendWindow(); |
| |
| // Make sure we fall out of slow start. |
| QuicByteCount saved_cwnd = sender_->GetCongestionWindow(); |
| LoseNPackets(1); |
| EXPECT_GT(saved_cwnd, sender_->GetCongestionWindow()); |
| |
| // Ack the rest of the outstanding packets to get out of recovery. |
| for (int i = 1; i < num_sent; ++i) { |
| AckNPackets(1); |
| } |
| EXPECT_EQ(0u, bytes_in_flight_); |
| |
| // Send a new window of data and ack all; cubic growth should occur. |
| saved_cwnd = sender_->GetCongestionWindow(); |
| num_sent = SendAvailableSendWindow(); |
| for (int i = 0; i < num_sent; ++i) { |
| AckNPackets(1); |
| } |
| EXPECT_LT(saved_cwnd, sender_->GetCongestionWindow()); |
| EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); |
| EXPECT_EQ(0u, bytes_in_flight_); |
| |
| // Quiescent time of 100 seconds |
| clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(100000)); |
| |
| // Send new window of data and ack one packet. Cubic epoch should have |
| // been reset; ensure cwnd increase is not dramatic. |
| saved_cwnd = sender_->GetCongestionWindow(); |
| SendAvailableSendWindow(); |
| AckNPackets(1); |
| EXPECT_NEAR(saved_cwnd, sender_->GetCongestionWindow(), kDefaultTCPMSS); |
| EXPECT_GT(kMaxCongestionWindowBytes, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, MultipleLossesInOneWindow) { |
| SendAvailableSendWindow(); |
| const QuicByteCount initial_window = sender_->GetCongestionWindow(); |
| LosePacket(acked_packet_number_ + 1); |
| const QuicByteCount post_loss_window = sender_->GetCongestionWindow(); |
| EXPECT_GT(initial_window, post_loss_window); |
| LosePacket(acked_packet_number_ + 3); |
| EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); |
| LosePacket(packet_number_ - 1); |
| EXPECT_EQ(post_loss_window, sender_->GetCongestionWindow()); |
| |
| // Lose a later packet and ensure the window decreases. |
| LosePacket(packet_number_); |
| EXPECT_GT(post_loss_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, ConfigureMaxInitialWindow) { |
| QuicConfig config; |
| |
| // Verify that kCOPT: kIW10 forces the congestion window to the default of 10. |
| QuicTagVector options; |
| options.push_back(kIW10); |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| EXPECT_EQ(10u * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, SetInitialCongestionWindow) { |
| EXPECT_NE(3u * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| sender_->SetInitialCongestionWindowInPackets(3); |
| EXPECT_EQ(3u * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, 2ConnectionCongestionAvoidanceAtEndOfRecovery) { |
| sender_->SetNumEmulatedConnections(2); |
| // Ack 10 packets in 5 acks to raise the CWND to 20. |
| const int kNumberOfAcks = 5; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| LoseNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. |
| expected_send_window = expected_send_window * sender_->GetRenoBeta(); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // No congestion window growth should occur in recovery phase, i.e., until the |
| // currently outstanding 20 packets are acked. |
| for (int i = 0; i < 10; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| EXPECT_TRUE(sender_->InRecovery()); |
| AckNPackets(2); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| EXPECT_FALSE(sender_->InRecovery()); |
| |
| // Out of recovery now. Congestion window should not grow for half an RTT. |
| size_t packets_in_send_window = expected_send_window / kDefaultTCPMSS; |
| SendAvailableSendWindow(); |
| AckNPackets(packets_in_send_window / 2 - 2); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Next ack should increase congestion window by 1MSS. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| expected_send_window += kDefaultTCPMSS; |
| packets_in_send_window += 1; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Congestion window should remain steady again for half an RTT. |
| SendAvailableSendWindow(); |
| AckNPackets(packets_in_send_window / 2 - 1); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Next ack should cause congestion window to grow by 1MSS. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| expected_send_window += kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, 1ConnectionCongestionAvoidanceAtEndOfRecovery) { |
| sender_->SetNumEmulatedConnections(1); |
| // Ack 10 packets in 5 acks to raise the CWND to 20. |
| const int kNumberOfAcks = 5; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| LoseNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. |
| expected_send_window *= kRenoBeta; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // No congestion window growth should occur in recovery phase, i.e., until the |
| // currently outstanding 20 packets are acked. |
| for (int i = 0; i < 10; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| EXPECT_TRUE(sender_->InRecovery()); |
| AckNPackets(2); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| EXPECT_FALSE(sender_->InRecovery()); |
| |
| // Out of recovery now. Congestion window should not grow during RTT. |
| for (uint64_t i = 0; i < expected_send_window / kDefaultTCPMSS - 2; i += 2) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| // Next ack should cause congestion window to grow by 1MSS. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| expected_send_window += kDefaultTCPMSS; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, BandwidthResumption) { |
| // Test that when provided with CachedNetworkParameters and opted in to the |
| // bandwidth resumption experiment, that the TcpCubicSenderPackets sets |
| // initial CWND appropriately. |
| |
| // Set some common values. |
| const QuicPacketCount kNumberOfPackets = 123; |
| const QuicBandwidth kBandwidthEstimate = |
| QuicBandwidth::FromBytesPerSecond(kNumberOfPackets * kDefaultTCPMSS); |
| const QuicTime::Delta kRttEstimate = QuicTime::Delta::FromSeconds(1); |
| |
| SendAlgorithmInterface::NetworkParams network_param; |
| network_param.bandwidth = kBandwidthEstimate; |
| network_param.rtt = kRttEstimate; |
| sender_->AdjustNetworkParameters(network_param); |
| EXPECT_EQ(kNumberOfPackets * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| |
| // Resume with an illegal value of 0 and verify the server ignores it. |
| SendAlgorithmInterface::NetworkParams network_param_no_bandwidth; |
| network_param_no_bandwidth.bandwidth = QuicBandwidth::Zero(); |
| network_param_no_bandwidth.rtt = kRttEstimate; |
| sender_->AdjustNetworkParameters(network_param_no_bandwidth); |
| EXPECT_EQ(kNumberOfPackets * kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| |
| // Resumed CWND is limited to be in a sensible range. |
| const QuicBandwidth kUnreasonableBandwidth = |
| QuicBandwidth::FromBytesPerSecond((kMaxResumptionCongestionWindow + 1) * |
| kDefaultTCPMSS); |
| SendAlgorithmInterface::NetworkParams network_param_large_bandwidth; |
| network_param_large_bandwidth.bandwidth = kUnreasonableBandwidth; |
| network_param_large_bandwidth.rtt = QuicTime::Delta::FromSeconds(1); |
| sender_->AdjustNetworkParameters(network_param_large_bandwidth); |
| EXPECT_EQ(kMaxResumptionCongestionWindow * kDefaultTCPMSS, |
| sender_->GetCongestionWindow()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, PaceBelowCWND) { |
| QuicConfig config; |
| |
| // Verify that kCOPT: kMIN4 forces the min CWND to 1 packet, but allows up |
| // to 4 to be sent. |
| QuicTagVector options; |
| options.push_back(kMIN4); |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| sender_->OnRetransmissionTimeout(true); |
| EXPECT_EQ(kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| EXPECT_TRUE(sender_->CanSend(kDefaultTCPMSS)); |
| EXPECT_TRUE(sender_->CanSend(2 * kDefaultTCPMSS)); |
| EXPECT_TRUE(sender_->CanSend(3 * kDefaultTCPMSS)); |
| EXPECT_FALSE(sender_->CanSend(4 * kDefaultTCPMSS)); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, NoPRR) { |
| QuicTime::Delta rtt = QuicTime::Delta::FromMilliseconds(100); |
| sender_->rtt_stats_.UpdateRtt(rtt, QuicTime::Delta::Zero(), QuicTime::Zero()); |
| |
| sender_->SetNumEmulatedConnections(1); |
| // Verify that kCOPT: kNPRR allows all packets to be sent, even if only one |
| // ack has been received. |
| QuicTagVector options; |
| options.push_back(kNPRR); |
| QuicConfig config; |
| QuicConfigPeer::SetReceivedConnectionOptions(&config, options); |
| sender_->SetFromConfig(config, Perspective::IS_SERVER); |
| SendAvailableSendWindow(); |
| LoseNPackets(9); |
| AckNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. |
| EXPECT_EQ(kRenoBeta * kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| const QuicPacketCount window_in_packets = |
| kRenoBeta * kDefaultWindowTCP / kDefaultTCPMSS; |
| const QuicBandwidth expected_pacing_rate = |
| QuicBandwidth::FromBytesAndTimeDelta(kRenoBeta * kDefaultWindowTCP, |
| sender_->rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(expected_pacing_rate, sender_->PacingRate(0)); |
| EXPECT_EQ(window_in_packets, |
| static_cast<uint64_t>(SendAvailableSendWindow())); |
| EXPECT_EQ(expected_pacing_rate, |
| sender_->PacingRate(kRenoBeta * kDefaultWindowTCP)); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, ResetAfterConnectionMigration) { |
| // Starts from slow start. |
| sender_->SetNumEmulatedConnections(1); |
| const int kNumberOfAcks = 10; |
| for (int i = 0; i < kNumberOfAcks; ++i) { |
| // Send our full send window. |
| SendAvailableSendWindow(); |
| AckNPackets(2); |
| } |
| SendAvailableSendWindow(); |
| QuicByteCount expected_send_window = |
| kDefaultWindowTCP + (kDefaultTCPMSS * 2 * kNumberOfAcks); |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| |
| // Loses a packet to exit slow start. |
| LoseNPackets(1); |
| |
| // We should now have fallen out of slow start with a reduced window. Slow |
| // start threshold is also updated. |
| expected_send_window *= kRenoBeta; |
| EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow()); |
| EXPECT_EQ(expected_send_window, sender_->GetSlowStartThreshold()); |
| |
| // Resets cwnd and slow start threshold on connection migrations. |
| sender_->OnConnectionMigration(); |
| EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow()); |
| EXPECT_EQ(kMaxCongestionWindowPackets * kDefaultTCPMSS, |
| sender_->GetSlowStartThreshold()); |
| EXPECT_FALSE(sender_->hybrid_slow_start().started()); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, DefaultMaxCwnd) { |
| RttStats rtt_stats; |
| QuicConnectionStats stats; |
| std::unique_ptr<SendAlgorithmInterface> sender(SendAlgorithmInterface::Create( |
| &clock_, &rtt_stats, /*unacked_packets=*/nullptr, kCubicBytes, |
| QuicRandom::GetInstance(), &stats, kInitialCongestionWindow, nullptr)); |
| |
| AckedPacketVector acked_packets; |
| LostPacketVector missing_packets; |
| QuicPacketCount max_congestion_window = |
| GetQuicFlag(quic_max_congestion_window); |
| for (uint64_t i = 1; i < max_congestion_window; ++i) { |
| acked_packets.clear(); |
| acked_packets.push_back( |
| AckedPacket(QuicPacketNumber(i), 1350, QuicTime::Zero())); |
| sender->OnCongestionEvent(true, sender->GetCongestionWindow(), clock_.Now(), |
| acked_packets, missing_packets); |
| } |
| EXPECT_EQ(max_congestion_window, |
| sender->GetCongestionWindow() / kDefaultTCPMSS); |
| } |
| |
| TEST_F(TcpCubicSenderBytesTest, LimitCwndIncreaseInCongestionAvoidance) { |
| // Enable Cubic. |
| sender_ = std::make_unique<TcpCubicSenderBytesPeer>(&clock_, false); |
| |
| int num_sent = SendAvailableSendWindow(); |
| |
| // Make sure we fall out of slow start. |
| QuicByteCount saved_cwnd = sender_->GetCongestionWindow(); |
| LoseNPackets(1); |
| EXPECT_GT(saved_cwnd, sender_->GetCongestionWindow()); |
| |
| // Ack the rest of the outstanding packets to get out of recovery. |
| for (int i = 1; i < num_sent; ++i) { |
| AckNPackets(1); |
| } |
| EXPECT_EQ(0u, bytes_in_flight_); |
| // Send a new window of data and ack all; cubic growth should occur. |
| saved_cwnd = sender_->GetCongestionWindow(); |
| num_sent = SendAvailableSendWindow(); |
| |
| // Ack packets until the CWND increases. |
| while (sender_->GetCongestionWindow() == saved_cwnd) { |
| AckNPackets(1); |
| SendAvailableSendWindow(); |
| } |
| // Bytes in flight may be larger than the CWND if the CWND isn't an exact |
| // multiple of the packet sizes being sent. |
| EXPECT_GE(bytes_in_flight_, sender_->GetCongestionWindow()); |
| saved_cwnd = sender_->GetCongestionWindow(); |
| |
| // Advance time 2 seconds waiting for an ack. |
| clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(2000)); |
| |
| // Ack two packets. The CWND should increase by only one packet. |
| AckNPackets(2); |
| EXPECT_EQ(saved_cwnd + kDefaultTCPMSS, sender_->GetCongestionWindow()); |
| } |
| |
| } // namespace test |
| } // namespace quic |