1 // Copyright (c) 2012 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 "quiche/quic/core/congestion_control/hybrid_slow_start.h"
6
7 #include <memory>
8 #include <utility>
9
10 #include "quiche/quic/platform/api/quic_test.h"
11
12 namespace quic {
13 namespace test {
14
15 class HybridSlowStartTest : public QuicTest {
16 protected:
HybridSlowStartTest()17 HybridSlowStartTest()
18 : one_ms_(QuicTime::Delta::FromMilliseconds(1)),
19 rtt_(QuicTime::Delta::FromMilliseconds(60)) {}
SetUp()20 void SetUp() override { slow_start_ = std::make_unique<HybridSlowStart>(); }
21 const QuicTime::Delta one_ms_;
22 const QuicTime::Delta rtt_;
23 std::unique_ptr<HybridSlowStart> slow_start_;
24 };
25
TEST_F(HybridSlowStartTest,Simple)26 TEST_F(HybridSlowStartTest, Simple) {
27 QuicPacketNumber packet_number(1);
28 QuicPacketNumber end_packet_number(3);
29 slow_start_->StartReceiveRound(end_packet_number);
30
31 EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
32
33 // Test duplicates.
34 EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number));
35
36 EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
37 EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
38
39 // Test without a new registered end_packet_number;
40 EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
41
42 end_packet_number = QuicPacketNumber(20);
43 slow_start_->StartReceiveRound(end_packet_number);
44 while (packet_number < end_packet_number) {
45 EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
46 }
47 EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
48 }
49
TEST_F(HybridSlowStartTest,Delay)50 TEST_F(HybridSlowStartTest, Delay) {
51 // We expect to detect the increase at +1/8 of the RTT; hence at a typical
52 // RTT of 60ms the detection will happen at 67.5 ms.
53 const int kHybridStartMinSamples = 8; // Number of acks required to trigger.
54
55 QuicPacketNumber end_packet_number(1);
56 slow_start_->StartReceiveRound(end_packet_number++);
57
58 // Will not trigger since our lowest RTT in our burst is the same as the long
59 // term RTT provided.
60 for (int n = 0; n < kHybridStartMinSamples; ++n) {
61 EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
62 rtt_ + QuicTime::Delta::FromMilliseconds(n), rtt_, 100));
63 }
64 slow_start_->StartReceiveRound(end_packet_number++);
65 for (int n = 1; n < kHybridStartMinSamples; ++n) {
66 EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
67 rtt_ + QuicTime::Delta::FromMilliseconds(n + 10), rtt_, 100));
68 }
69 // Expect to trigger since all packets in this burst was above the long term
70 // RTT provided.
71 EXPECT_TRUE(slow_start_->ShouldExitSlowStart(
72 rtt_ + QuicTime::Delta::FromMilliseconds(10), rtt_, 100));
73 }
74
75 } // namespace test
76 } // namespace quic
77