Index: net/quic/core/congestion_control/bbr_sender_test.cc |
diff --git a/net/quic/core/congestion_control/bbr_sender_test.cc b/net/quic/core/congestion_control/bbr_sender_test.cc |
index 400b3d4eb07c7e7d23fc7dcb94052fdfffea2d5e..a0d4b505d41791a6d6c971217732a80d463971d8 100644 |
--- a/net/quic/core/congestion_control/bbr_sender_test.cc |
+++ b/net/quic/core/congestion_control/bbr_sender_test.cc |
@@ -91,12 +91,13 @@ |
receiver_multiplexer_("Receiver multiplexer", |
{&receiver_, &competing_receiver_}) { |
// These will be changed by the appropriate tests as necessary. |
+ FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = false; |
FLAGS_quic_reloadable_flag_quic_bbr_slow_recent_delivery = false; |
FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = false; |
// TODO(ianswett): Determine why tests become flaky with CWND based on SRTT. |
FLAGS_quic_reloadable_flag_quic_bbr_base_cwnd_on_srtt = false; |
FLAGS_quic_reloadable_flag_quic_bbr_extra_conservation = true; |
- FLAGS_quic_reloadable_flag_quic_bbr_fix_conservation2 = true; |
+ FLAGS_quic_reloadable_flag_quic_bbr_fix_conservation = true; |
rtt_stats_ = bbr_sender_.connection()->sent_packet_manager().GetRttStats(); |
sender_ = SetupBbrSender(&bbr_sender_); |
@@ -319,6 +320,34 @@ |
// smoothed rtt. |
EXPECT_GE(kTestRtt * 4, rtt_stats_->smoothed_rtt()); |
ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.12f); |
+} |
+ |
+TEST_F(BbrSenderTest, SimpleTransfer2RTTAggregationKeepSending) { |
+ FLAGS_quic_reloadable_flag_quic_bbr_ack_aggregation_bytes = false; |
+ FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = false; |
+ FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = true; |
+ CreateDefaultSetup(); |
+ // 2 RTTs of aggregation, with a max of 10kb. |
+ EnableAggregation(10 * 1024, 2 * kTestRtt); |
+ |
+ // Transfer 12MB. |
+ DoSimpleTransfer(12 * 1024 * 1024, QuicTime::Delta::FromSeconds(35)); |
+ EXPECT_EQ(BbrSender::PROBE_BW, sender_->ExportDebugState().mode); |
+ // It's possible to read a bandwidth as much as 50% too high with aggregation. |
+ EXPECT_LE(kTestLinkBandwidth * 0.95f, |
+ sender_->ExportDebugState().max_bandwidth); |
+ // TODO(ianswett): Tighten this bound once we understand why BBR is |
+ // overestimating bandwidth with aggregation. b/36022633 |
+ EXPECT_GE(kTestLinkBandwidth * 1.5f, |
+ sender_->ExportDebugState().max_bandwidth); |
+ // TODO(ianswett): Expect 0 packets are lost once BBR no longer measures |
+ // bandwidth higher than the link rate. |
+ // TODO(vasilvv): figure out why the line below is occasionally flaky. |
+ // EXPECT_FALSE(sender_->ExportDebugState().last_sample_is_app_limited); |
+ // The margin here is high, because the aggregation greatly increases |
+ // smoothed rtt. |
+ EXPECT_GE(kTestRtt * 4.5, rtt_stats_->smoothed_rtt()); |
+ ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.1f); |
} |
// Test a simple long data transfer with 2 rtts of aggregation. |
@@ -357,11 +386,49 @@ |
ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.1f); |
} |
+TEST_F(BbrSenderTest, SimpleTransferAckDecimationKeepSending) { |
+ FLAGS_quic_reloadable_flag_quic_bbr_ack_aggregation_bytes = false; |
+ FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = true; |
+ FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = true; |
+ // Decrease the CWND gain so extra CWND is required with stretch acks. |
+ FLAGS_quic_bbr_cwnd_gain = 1.0; |
+ sender_ = new BbrSender( |
+ rtt_stats_, |
+ QuicSentPacketManagerPeer::GetUnackedPacketMap( |
+ QuicConnectionPeer::GetSentPacketManager(bbr_sender_.connection())), |
+ kInitialCongestionWindowPackets, kDefaultMaxCongestionWindowPackets, |
+ &random_); |
+ QuicConnectionPeer::SetSendAlgorithm(bbr_sender_.connection(), sender_); |
+ // Enable Ack Decimation on the receiver. |
+ QuicConnectionPeer::SetAckMode(receiver_.connection(), |
+ QuicConnection::AckMode::ACK_DECIMATION); |
+ CreateDefaultSetup(); |
+ |
+ // Transfer 12MB. |
+ DoSimpleTransfer(12 * 1024 * 1024, QuicTime::Delta::FromSeconds(35)); |
+ EXPECT_EQ(BbrSender::PROBE_BW, sender_->ExportDebugState().mode); |
+ // It's possible to read a bandwidth as much as 50% too high with aggregation. |
+ EXPECT_LE(kTestLinkBandwidth * 0.95f, |
+ sender_->ExportDebugState().max_bandwidth); |
+ // TODO(ianswett): Tighten this bound once we understand why BBR is |
+ // overestimating bandwidth with aggregation. b/36022633 |
+ EXPECT_GE(kTestLinkBandwidth * 1.5f, |
+ sender_->ExportDebugState().max_bandwidth); |
+ // TODO(ianswett): Expect 0 packets are lost once BBR no longer measures |
+ // bandwidth higher than the link rate. |
+ EXPECT_FALSE(sender_->ExportDebugState().last_sample_is_app_limited); |
+ // The margin here is high, because the aggregation greatly increases |
+ // smoothed rtt. |
+ EXPECT_GE(kTestRtt * 2, rtt_stats_->smoothed_rtt()); |
+ ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.1f); |
+} |
+ |
// Test a simple long data transfer with 2 rtts of aggregation. |
TEST_F(BbrSenderTest, |
SimpleTransfer2RTTAggregationBytesWithIncreasedInflightLimit) { |
FLAGS_quic_reloadable_flag_quic_bbr_ack_aggregation_bytes = false; |
FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = false; |
+ FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = false; |
FLAGS_quic_reloadable_flag_quic_bbr_slow_recent_delivery = true; |
FLAGS_quic_bbr_slow_delivery_threshold_multiplier = 0.5; |
FLAGS_quic_bbr_slow_delivery_cwnd_gain = 4.0; |
@@ -427,12 +494,18 @@ |
ASSERT_EQ(BbrSender::CONSERVATION, |
sender_->ExportDebugState().recovery_state); |
- simulator_result = simulator_.RunUntilOrTimeout( |
- [this]() { |
+ const QuicByteCount cwnd_at_recovery_start = sender_->GetCongestionWindow(); |
+ simulator_result = simulator_.RunUntilOrTimeout( |
+ [this, cwnd_at_recovery_start]() { |
+ // Ensure that the CWND never drops due to conservation. |
+ if (sender_->GetCongestionWindow() < cwnd_at_recovery_start) { |
+ return true; |
+ } |
return sender_->ExportDebugState().recovery_state != |
BbrSender::CONSERVATION; |
}, |
timeout); |
+ ASSERT_GE(sender_->GetCongestionWindow(), cwnd_at_recovery_start); |
ASSERT_TRUE(simulator_result); |
ASSERT_EQ(BbrSender::GROWTH, sender_->ExportDebugState().recovery_state); |