Test for all our CC algorithms under >1 network scenarios.

net/quic/core/congestion_control/send_algorithm_test.cc

Index: net/quic/core/congestion_control/send_algorithm_test.cc
diff --git a/net/quic/core/congestion_control/send_algorithm_test.cc b/net/quic/core/congestion_control/send_algorithm_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..75bacfbb9c460695c08b91a35e9450523d1e0581
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+++ b/net/quic/core/congestion_control/send_algorithm_test.cc
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+// Copyright 2013 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 <algorithm>
+#include <map>
+#include <memory>
+
+#include "base/logging.h"
+#include "net/quic/core/congestion_control/rtt_stats.h"
+#include "net/quic/core/congestion_control/send_algorithm_interface.h"
+#include "net/quic/core/quic_types.h"
+#include "net/quic/core/quic_utils.h"
+#include "net/quic/test_tools/mock_clock.h"
+#include "net/quic/test_tools/quic_config_peer.h"
+#include "net/quic/test_tools/quic_connection_peer.h"
+#include "net/quic/test_tools/quic_sent_packet_manager_peer.h"
+#include "net/quic/test_tools/quic_test_utils.h"
+#include "net/quic/test_tools/simulator/quic_endpoint.h"
+#include "net/quic/test_tools/simulator/simulator.h"
+#include "net/quic/test_tools/simulator/switch.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using std::string;
+
+namespace net {
+namespace test {
+namespace {
+
+// Use the initial CWND of 10, as 32 is too much for the test network.
+const uint32_t kInitialCongestionWindowPackets = 10;
+
+// Test network parameters.  Here, the topology of the network is:
+//
+//           QUIC Sender
+//               |
+//               |  <-- local link
+//               |
+//        Network switch
+//               *  <-- the bottleneck queue in the direction
+//               |          of the receiver
+//               |
+//               |  <-- test link
+//               |
+//               |
+//           Receiver
+//
+// When setting the bandwidth of the local link and test link, choose
+// a bandwidth lower than 20Mbps, as the clock-granularity of the
+// simulator can only handle a granularity of 1us.
+
+// Default settings between the switch and the sender.
+const QuicBandwidth kLocalLinkBandwidth =
+    QuicBandwidth::FromKBitsPerSecond(10000);
+const QuicTime::Delta kLocalPropagationDelay =
+    QuicTime::Delta::FromMilliseconds(2);
+
+// Wired network settings.  A typical desktop network setup, a
+// high-bandwidth, 30ms test link to the receiver.
+const QuicBandwidth kTestLinkWiredBandwidth =
+    QuicBandwidth::FromKBitsPerSecond(4000);
+const QuicTime::Delta kTestLinkWiredPropagationDelay =
+    QuicTime::Delta::FromMilliseconds(30);
+const QuicTime::Delta kTestWiredTransferTime =
+    kTestLinkWiredBandwidth.TransferTime(kMaxPacketSize) +
+    kLocalLinkBandwidth.TransferTime(kMaxPacketSize);
+const QuicTime::Delta kTestWiredRtt =
+    (kTestLinkWiredPropagationDelay + kLocalPropagationDelay +
+     kTestWiredTransferTime) *
+    2;
+const QuicByteCount kTestWiredBdp = kTestWiredRtt * kTestLinkWiredBandwidth;
+
+// Small BDP, Bandwidth-policed network settings.  In this scenario,
+// the receiver has a low-bandwidth, short propagation-delay link,
+// resulting in a small BDP.  We model the policer by setting the
+// queue size to only one packet.
+const QuicBandwidth kTestLinkLowBdpBandwidth =
+    QuicBandwidth::FromKBitsPerSecond(200);
+const QuicTime::Delta kTestLinkLowBdpPropagationDelay =
+    QuicTime::Delta::FromMilliseconds(30);
+const QuicByteCount kTestPolicerQueue = kMaxPacketSize;
+
+// Satellite network settings.  In a satellite network, the bottleneck
+// buffer is typically sized for non-satellite links , but the
+// propagation delay of the test link to the receiver is as much as a
+// quarter second.
+const QuicTime::Delta kTestSatellitePropagationDelay =
+    QuicTime::Delta::FromMilliseconds(250);
+
+// Cellular scenarios.  In a cellular network, the bottleneck queue at
+// the edge of the network can be as great as 3MB.
+const QuicBandwidth kTestLink2GBandwidth =
+    QuicBandwidth::FromKBitsPerSecond(100);
+const QuicBandwidth kTestLink3GBandwidth =
+    QuicBandwidth::FromKBitsPerSecond(1500);
+const QuicByteCount kCellularQueue = 3 * 1024 * 1024;
+const QuicTime::Delta kTestCellularPropagationDelay =
+    QuicTime::Delta::FromMilliseconds(40);
+
+const char* CongestionControlTypeToString(CongestionControlType cc_type) {
+  switch (cc_type) {
+    case kCubic:
+      return "CUBIC_PACKETS";
+    case kCubicBytes:
+      return "CUBIC_BYTES";
+    case kReno:
+      return "RENO_PACKETS";
+    case kRenoBytes:
+      return "RENO_BYTES";
+    case kBBR:
+      return "BBR";
+    default:
+      DLOG(FATAL) << "Unexpected CongestionControlType";
+      return nullptr;
+  }
+}
+
+struct TestParams {
+  explicit TestParams(CongestionControlType congestion_control_type)
+      : congestion_control_type(congestion_control_type) {}
+
+  friend std::ostream& operator<<(std::ostream& os, const TestParams& p) {
+    os << "{ congestion_control_type: "
+       << CongestionControlTypeToString(p.congestion_control_type);
+    os << " }";
+    return os;
+  }
+
+  CongestionControlType congestion_control_type;
+};
+
+string TestParamToString(const testing::TestParamInfo<TestParams>& params) {
+  return CongestionControlTypeToString(params.param.congestion_control_type);
+}
+
+// Constructs various test permutations.
+std::vector<TestParams> GetTestParams() {
+  std::vector<TestParams> params;
+  for (const CongestionControlType congestion_control_type :
+       {kBBR, kCubic, kCubicBytes, kReno, kRenoBytes}) {
+    params.push_back(TestParams(congestion_control_type));
+  }
+  return params;
+}
+
+}  // namespace
+
+class SendAlgorithmTest : public ::testing::TestWithParam<TestParams> {
+ protected:
+  SendAlgorithmTest()
+      : simulator_(),
+        quic_sender_(&simulator_,
+                     "QUIC sender",
+                     "Receiver",
+                     Perspective::IS_CLIENT,
+                     42),
+        receiver_(&simulator_,
+                  "Receiver",
+                  "QUIC sender",
+                  Perspective::IS_SERVER,
+                  42) {
+    rtt_stats_ = quic_sender_.connection()->sent_packet_manager().GetRttStats();
+    sender_ = SendAlgorithmInterface::Create(
+        simulator_.GetClock(), rtt_stats_,
+        QuicSentPacketManagerPeer::GetUnackedPacketMap(
+            QuicConnectionPeer::GetSentPacketManager(quic_sender_.connection(),
+                                                     kDefaultPathId)),
+        GetParam().congestion_control_type, &random_, &stats_,
+        kInitialCongestionWindowPackets);
+
+    if (FLAGS_quic_fix_cubic_convex_mode) {
+      QuicConfig client_config;
+      QuicTagVector options;
+      options.push_back(kCCVX);
+      client_config.SetInitialReceivedConnectionOptions(options);
+      sender_->SetFromConfig(client_config, Perspective::IS_SERVER);
+    }
+
+    QuicConnectionPeer::SetSendAlgorithm(quic_sender_.connection(),
+                                         kDefaultPathId, sender_);
+
+    clock_ = simulator_.GetClock();
+    simulator_.set_random_generator(&random_);
+
+    uint64_t seed = QuicRandom::GetInstance()->RandUint64();
+    random_.set_seed(seed);
+    VLOG(1) << "SendAlgorithmTest simulator set up.  Seed: " << seed;
+  }
+
+  // Creates a simulated network, with default settings between the
+  // sender and the switch and the given settings from the switch to
+  // the receiver.
+  void CreateSetup(const QuicBandwidth& test_bandwidth,
+                   const QuicTime::Delta& test_link_delay,
+                   QuicByteCount bottleneck_queue_length) {
+    switch_.reset(new simulator::Switch(&simulator_, "Switch", 8,
+                                        bottleneck_queue_length));
+    quic_sender_link_.reset(new simulator::SymmetricLink(
+        &quic_sender_, switch_->port(1), kLocalLinkBandwidth,
+        kLocalPropagationDelay));
+    receiver_link_.reset(new simulator::SymmetricLink(
+        &receiver_, switch_->port(2), test_bandwidth, test_link_delay));
+  }
+
+  void DoSimpleTransfer(QuicByteCount transfer_size, QuicTime::Delta deadline) {
+    quic_sender_.AddBytesToTransfer(transfer_size);
+    bool simulator_result = simulator_.RunUntilOrTimeout(
+        [this]() { return quic_sender_.bytes_to_transfer() == 0; }, deadline);
+    EXPECT_TRUE(simulator_result)
+        << "Simple transfer failed.  Bytes remaining: "
+        << quic_sender_.bytes_to_transfer();
+  }
+
+  void SendBursts(size_t number_of_bursts,
+                  QuicByteCount bytes,
+                  QuicTime::Delta rtt,
+                  QuicTime::Delta wait_time) {
+    ASSERT_EQ(0u, quic_sender_.bytes_to_transfer());
+    for (size_t i = 0; i < number_of_bursts; i++) {
+      quic_sender_.AddBytesToTransfer(bytes);
+
+      // Transfer data and wait for three seconds between each transfer.
+      simulator_.RunFor(wait_time);
+
+      // Ensure the connection did not time out.
+      ASSERT_TRUE(quic_sender_.connection()->connected());
+      ASSERT_TRUE(receiver_.connection()->connected());
+    }
+
+    simulator_.RunFor(wait_time + rtt);
+    EXPECT_EQ(0u, quic_sender_.bytes_to_transfer());
+  }
+
+  // Estimates the elapsed time for a given transfer size, given the
+  // bottleneck bandwidth and link propagation delay.
+  QuicTime::Delta EstimatedElapsedTime(
+      QuicByteCount transfer_size_bytes,
+      QuicBandwidth test_link_bandwidth,
+      const QuicTime::Delta& test_link_delay) const {
+    return test_link_bandwidth.TransferTime(transfer_size_bytes) +
+           2 * test_link_delay;
+  }
+
+  QuicTime QuicSenderStartTime() {
+    return quic_sender_.connection()->GetStats().connection_creation_time;
+  }
+
+  void PrintTransferStats() {
+    VLOG(1) << "Summary for scenario " << GetParam();
+    VLOG(1) << "Sender stats is " << quic_sender_.connection()->GetStats();
+    VLOG(1) << "Connection elapsed time: "
+            << (clock_->Now() - QuicSenderStartTime()).ToMilliseconds()
+            << " (ms)";
+  }
+
+  simulator::Simulator simulator_;
+  simulator::QuicEndpoint quic_sender_;
+  simulator::QuicEndpoint receiver_;
+  std::unique_ptr<simulator::Switch> switch_;
+  std::unique_ptr<simulator::SymmetricLink> quic_sender_link_;
+  std::unique_ptr<simulator::SymmetricLink> receiver_link_;
+  QuicConnectionStats stats_;
+
+  SimpleRandom random_;
+
+  // Owned by different components of the connection.
+  const QuicClock* clock_;
+  const RttStats* rtt_stats_;
+  SendAlgorithmInterface* sender_;
+};
+
+INSTANTIATE_TEST_CASE_P(SendAlgorithmTests,
+                        SendAlgorithmTest,
+                        ::testing::ValuesIn(GetTestParams()),
+                        TestParamToString);
+
+// Test a simple long data transfer in the default setup.
+TEST_P(SendAlgorithmTest, SimpleWiredNetworkTransfer) {
+  CreateSetup(kTestLinkWiredBandwidth, kTestLinkWiredPropagationDelay,
+              kTestWiredBdp);
+  const QuicByteCount kTransferSizeBytes = 12 * 1024 * 1024;
+  const QuicTime::Delta maximum_elapsed_time =
+      EstimatedElapsedTime(kTransferSizeBytes, kTestLinkWiredBandwidth,
+                           kTestLinkWiredPropagationDelay) *
+      1.2;
+  DoSimpleTransfer(kTransferSizeBytes, maximum_elapsed_time);
+  PrintTransferStats();
+}
+
+TEST_P(SendAlgorithmTest, LowBdpPolicedNetworkTransfer) {
+  CreateSetup(kTestLinkLowBdpBandwidth, kTestLinkLowBdpPropagationDelay,
+              kTestPolicerQueue);
+  const QuicByteCount kTransferSizeBytes = 5 * 1024 * 1024;
+  const QuicTime::Delta maximum_elapsed_time =
+      EstimatedElapsedTime(kTransferSizeBytes, kTestLinkLowBdpBandwidth,
+                           kTestLinkLowBdpPropagationDelay) *
+      1.2;
+  DoSimpleTransfer(kTransferSizeBytes, maximum_elapsed_time);
+  PrintTransferStats();
+}
+
+TEST_P(SendAlgorithmTest, AppLimitedBurstsOverWiredNetwork) {
+  CreateSetup(kTestLinkWiredBandwidth, kTestLinkWiredPropagationDelay,
+              kTestWiredBdp);
+  const QuicByteCount kBurstSizeBytes = 512;
+  const int kNumBursts = 20;
+  const QuicTime::Delta kWaitTime = QuicTime::Delta::FromSeconds(3);
+  SendBursts(kNumBursts, kBurstSizeBytes, kTestWiredRtt, kWaitTime);
+  PrintTransferStats();
+
+  const QuicTime::Delta estimated_burst_time =
+      EstimatedElapsedTime(kBurstSizeBytes, kTestLinkWiredBandwidth,
+                           kTestLinkWiredPropagationDelay) +
+      kWaitTime;
+  const QuicTime::Delta max_elapsed_time =
+      kNumBursts * estimated_burst_time + kWaitTime;
+  const QuicTime::Delta actual_elapsed_time =
+      clock_->Now() - QuicSenderStartTime();
+  EXPECT_GE(max_elapsed_time, actual_elapsed_time);
+}
+
+TEST_P(SendAlgorithmTest, SatelliteNetworkTransfer) {
+  CreateSetup(kTestLinkWiredBandwidth, kTestSatellitePropagationDelay,
+              kTestWiredBdp);
+  const QuicByteCount kTransferSizeBytes = 20 * 1024 * 1024;
+  const QuicTime::Delta maximum_elapsed_time =
+      EstimatedElapsedTime(kTransferSizeBytes, kTestLinkWiredBandwidth,
+                           kTestSatellitePropagationDelay) *
+      1.25;
+  DoSimpleTransfer(kTransferSizeBytes, maximum_elapsed_time);
+  PrintTransferStats();
+}
+
+TEST_P(SendAlgorithmTest, 2GNetworkTransfer) {
+  CreateSetup(kTestLink2GBandwidth, kTestCellularPropagationDelay,
+              kCellularQueue);
+  const QuicByteCount kTransferSizeBytes = 1024 * 1024;
+  const QuicTime::Delta maximum_elapsed_time =
+      EstimatedElapsedTime(kTransferSizeBytes, kTestLink2GBandwidth,
+                           kTestCellularPropagationDelay) *
+      1.2;
+  DoSimpleTransfer(kTransferSizeBytes, maximum_elapsed_time);
+  PrintTransferStats();
+}
+
+TEST_P(SendAlgorithmTest, 3GNetworkTransfer) {
+  CreateSetup(kTestLink3GBandwidth, kTestCellularPropagationDelay,
+              kCellularQueue);
+  const QuicByteCount kTransferSizeBytes = 5 * 1024 * 1024;
+  const QuicTime::Delta maximum_elapsed_time =
+      EstimatedElapsedTime(kTransferSizeBytes, kTestLink3GBandwidth,
+                           kTestCellularPropagationDelay) *
+      1.2;
+  DoSimpleTransfer(kTransferSizeBytes, maximum_elapsed_time);
+  PrintTransferStats();
+}
+
+}  // namespace test
+}  // namespace net