Land Recent QUIC Changes.

net/quic/congestion_control/cubic_test.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/logging.h"
 #include "net/quic/congestion_control/cubic.h"
+#include "net/quic/quic_connection_stats.h"
 #include "net/quic/test_tools/mock_clock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
 namespace test {
 
 const float kBeta = 0.7f;  // Default Cubic backoff factor.
 const uint32 kNumConnections = 2;
 const float kNConnectionBeta = (kNumConnections - 1 + kBeta) / kNumConnections;
 const float kNConnectionAlpha = 3 * kNumConnections * kNumConnections *
       (1 - kNConnectionBeta) / (1 + kNConnectionBeta);
 
 class CubicTest : public ::testing::Test {
  protected:
   CubicTest()
       : one_ms_(QuicTime::Delta::FromMilliseconds(1)),
         hundred_ms_(QuicTime::Delta::FromMilliseconds(100)),
-        cubic_(&clock_) {
+        cubic_(&clock_, &stats_) {
   }
   const QuicTime::Delta one_ms_;
   const QuicTime::Delta hundred_ms_;
   MockClock clock_;
+  QuicConnectionStats stats_;
   Cubic cubic_;
 };
 
 TEST_F(CubicTest, AboveOrigin) {
   // Convex growth.
   const QuicTime::Delta rtt_min = hundred_ms_;
   uint32 current_cwnd = 10;
   uint32 expected_cwnd = current_cwnd + 1;
   // Initialize the state.
   clock_.AdvanceTime(one_ms_);
   EXPECT_EQ(expected_cwnd,
             cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min));
   current_cwnd = expected_cwnd;
   // Normal TCP phase.
   for (int i = 0; i < 48; ++i) {
     for (uint32 n = 1; n < current_cwnd / kNConnectionAlpha; ++n) {
       // Call once per ACK.
       EXPECT_NEAR(current_cwnd,
                   cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min), 1);
     }
     clock_.AdvanceTime(hundred_ms_);
     current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
     EXPECT_NEAR(expected_cwnd, current_cwnd, 1);
     expected_cwnd++;
   }
   // Cubic phase.
-  for (int j = 48; j < 100; ++j) {
+  for (int i = 0; i < 52; ++i) {
     for (uint32 n = 1; n < current_cwnd; ++n) {
       // Call once per ACK.
       EXPECT_EQ(current_cwnd,
                 cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min));
     }
     clock_.AdvanceTime(hundred_ms_);
     current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
   }
-  float elapsed_time_s = 10.0f + 0.1f;  // We need to add the RTT here.
+  // Total time elapsed so far; add min_rtt (0.1s) here as well.
+  float elapsed_time_s = 10.0f + 0.1f;
+  // expected_cwnd is initial value of cwnd + K * t^3, where K = 0.4.
   expected_cwnd = 11 + (elapsed_time_s * elapsed_time_s * elapsed_time_s * 410)
       / 1024;
   EXPECT_EQ(expected_cwnd, current_cwnd);
 }
 
+TEST_F(CubicTest, CwndIncreaseStatsDuringConvexRegion) {
+  const QuicTime::Delta rtt_min = hundred_ms_;
+  uint32 current_cwnd = 10;
+  uint32 expected_cwnd = current_cwnd + 1;
+  // Initialize controller state.
+  clock_.AdvanceTime(one_ms_);
+  expected_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+  current_cwnd = expected_cwnd;
+  // Testing Reno mode increase.
+  for (int i = 0; i < 48; ++i) {
+    for (uint32 n = 1; n < current_cwnd / kNConnectionAlpha; ++n) {
+      // Call once per ACK, causing cwnd growth in Reno mode.
+      cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+    }
+    // Advance current time so that cwnd update is allowed to happen by Cubic.
+    clock_.AdvanceTime(hundred_ms_);
+    current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+    EXPECT_NEAR(expected_cwnd - 10, stats_.cwnd_increase_reno_mode, 1);
+    EXPECT_NEAR(1u, stats_.cwnd_increase_cubic_mode, 1);
+    expected_cwnd++;
+  }
+  uint32 old_cwnd = current_cwnd;
+  stats_.cwnd_increase_cubic_mode = 0;
+  stats_.cwnd_increase_reno_mode = 0;
+
+  // Testing Cubic mode increase.
+  for (int i = 0; i < 52; ++i) {
+    for (uint32 n = 1; n < current_cwnd; ++n) {
+      // Call once per ACK.
+      cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+    }
+    clock_.AdvanceTime(hundred_ms_);
+    current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+  }
+  // Total time elapsed so far; add min_rtt (0.1s) here as well.
+  float elapsed_time_s = 10.0f + 0.1f;
+  // expected_cwnd is initial value of cwnd + K * t^3, where K = 0.4.
+  expected_cwnd = 11 + (elapsed_time_s * elapsed_time_s * elapsed_time_s * 410)
+      / 1024;
+  EXPECT_EQ(expected_cwnd - old_cwnd, stats_.cwnd_increase_cubic_mode);
+  EXPECT_EQ(0u, stats_.cwnd_increase_reno_mode);
+}
+
+
 TEST_F(CubicTest, LossEvents) {
   const QuicTime::Delta rtt_min = hundred_ms_;
   uint32 current_cwnd = 422;
   uint32 expected_cwnd = current_cwnd + 1;
   // Initialize the state.
   clock_.AdvanceTime(one_ms_);
   EXPECT_EQ(expected_cwnd,
             cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min));
   expected_cwnd = static_cast<int>(current_cwnd * kNConnectionBeta);
   EXPECT_EQ(expected_cwnd,
@@ skipping 11 matching lines @@
   // Initialize the state.
   clock_.AdvanceTime(one_ms_);
   EXPECT_EQ(expected_cwnd,
             cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min));
   expected_cwnd = static_cast<int>(current_cwnd * kNConnectionBeta);
   EXPECT_EQ(expected_cwnd,
             cubic_.CongestionWindowAfterPacketLoss(current_cwnd));
   current_cwnd = expected_cwnd;
   // First update after loss to initialize the epoch.
   current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
+  uint32 old_cwnd =  current_cwnd;
   // Cubic phase.
+  stats_.cwnd_increase_cubic_mode = 0;
+  stats_.cwnd_increase_reno_mode = 0;
   for (int i = 0; i < 40 ; ++i) {
     clock_.AdvanceTime(hundred_ms_);
     current_cwnd = cubic_.CongestionWindowAfterAck(current_cwnd, rtt_min);
   }
   expected_cwnd = 422;
   EXPECT_EQ(expected_cwnd, current_cwnd);
+  EXPECT_EQ(expected_cwnd - old_cwnd, stats_.cwnd_increase_cubic_mode);
+  EXPECT_EQ(0u, stats_.cwnd_increase_reno_mode);
 }
 
 }  // namespace test
 }  // namespace net