| // Copyright 2014 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/rtt_stats.h" |
| |
| #include <cmath> |
| |
| #include "quiche/quic/platform/api/quic_test.h" |
| #include "quiche/quic/test_tools/quic_test_utils.h" |
| |
| using testing::Message; |
| |
| namespace quic { |
| namespace test { |
| |
| class RttStatsTest : public QuicTest { |
| protected: |
| RttStats rtt_stats_; |
| }; |
| |
| TEST_F(RttStatsTest, DefaultsBeforeUpdate) { |
| EXPECT_LT(QuicTime::Delta::Zero(), rtt_stats_.initial_rtt()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.min_rtt()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.smoothed_rtt()); |
| } |
| |
| TEST_F(RttStatsTest, SmoothedRtt) { |
| // Verify that ack_delay is ignored in the first measurement. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(300), |
| QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.smoothed_rtt()); |
| // Verify that a plausible ack delay increases the max ack delay. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(400), |
| QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.smoothed_rtt()); |
| // Verify that Smoothed RTT includes max ack delay if it's reasonable. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(350), |
| QuicTime::Delta::FromMilliseconds(50), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300), rtt_stats_.smoothed_rtt()); |
| // Verify that large erroneous ack_delay does not change Smoothed RTT. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(200), |
| QuicTime::Delta::FromMilliseconds(300), |
| QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMicroseconds(287500), |
| rtt_stats_.smoothed_rtt()); |
| } |
| |
| // Ensure that the potential rounding artifacts in EWMA calculation do not cause |
| // the SRTT to drift too far from the exact value. |
| TEST_F(RttStatsTest, SmoothedRttStability) { |
| for (size_t time = 3; time < 20000; time++) { |
| RttStats stats; |
| for (size_t i = 0; i < 100; i++) { |
| stats.UpdateRtt(QuicTime::Delta::FromMicroseconds(time), |
| QuicTime::Delta::FromMilliseconds(0), QuicTime::Zero()); |
| int64_t time_delta_us = stats.smoothed_rtt().ToMicroseconds() - time; |
| ASSERT_LE(std::abs(time_delta_us), 1); |
| } |
| } |
| } |
| |
| TEST_F(RttStatsTest, PreviousSmoothedRtt) { |
| // Verify that ack_delay is corrected for in Smoothed RTT. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(200), |
| QuicTime::Delta::FromMilliseconds(0), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.previous_srtt()); |
| // Ensure the previous SRTT is 200ms after a 100ms sample. |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(100), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMicroseconds(187500).ToMicroseconds(), |
| rtt_stats_.smoothed_rtt().ToMicroseconds()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.previous_srtt()); |
| } |
| |
| TEST_F(RttStatsTest, MinRtt) { |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(200), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.min_rtt()); |
| rtt_stats_.UpdateRtt( |
| QuicTime::Delta::FromMilliseconds(10), QuicTime::Delta::Zero(), |
| QuicTime::Zero() + QuicTime::Delta::FromMilliseconds(10)); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt()); |
| rtt_stats_.UpdateRtt( |
| QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(), |
| QuicTime::Zero() + QuicTime::Delta::FromMilliseconds(20)); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt()); |
| rtt_stats_.UpdateRtt( |
| QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(), |
| QuicTime::Zero() + QuicTime::Delta::FromMilliseconds(30)); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt()); |
| rtt_stats_.UpdateRtt( |
| QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(), |
| QuicTime::Zero() + QuicTime::Delta::FromMilliseconds(40)); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt()); |
| // Verify that ack_delay does not go into recording of min_rtt_. |
| rtt_stats_.UpdateRtt( |
| QuicTime::Delta::FromMilliseconds(7), |
| QuicTime::Delta::FromMilliseconds(2), |
| QuicTime::Zero() + QuicTime::Delta::FromMilliseconds(50)); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(7), rtt_stats_.min_rtt()); |
| } |
| |
| TEST_F(RttStatsTest, ExpireSmoothedMetrics) { |
| QuicTime::Delta initial_rtt = QuicTime::Delta::FromMilliseconds(10); |
| rtt_stats_.UpdateRtt(initial_rtt, QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(initial_rtt, rtt_stats_.min_rtt()); |
| EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt()); |
| |
| EXPECT_EQ(0.5 * initial_rtt, rtt_stats_.mean_deviation()); |
| |
| // Update once with a 20ms RTT. |
| QuicTime::Delta doubled_rtt = 2 * initial_rtt; |
| rtt_stats_.UpdateRtt(doubled_rtt, QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(1.125 * initial_rtt, rtt_stats_.smoothed_rtt()); |
| |
| // Expire the smoothed metrics, increasing smoothed rtt and mean deviation. |
| rtt_stats_.ExpireSmoothedMetrics(); |
| EXPECT_EQ(doubled_rtt, rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(0.875 * initial_rtt, rtt_stats_.mean_deviation()); |
| |
| // Now go back down to 5ms and expire the smoothed metrics, and ensure the |
| // mean deviation increases to 15ms. |
| QuicTime::Delta half_rtt = 0.5 * initial_rtt; |
| rtt_stats_.UpdateRtt(half_rtt, QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_GT(doubled_rtt, rtt_stats_.smoothed_rtt()); |
| EXPECT_LT(initial_rtt, rtt_stats_.mean_deviation()); |
| } |
| |
| TEST_F(RttStatsTest, UpdateRttWithBadSendDeltas) { |
| QuicTime::Delta initial_rtt = QuicTime::Delta::FromMilliseconds(10); |
| rtt_stats_.UpdateRtt(initial_rtt, QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(initial_rtt, rtt_stats_.min_rtt()); |
| EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt()); |
| |
| std::vector<QuicTime::Delta> bad_send_deltas; |
| bad_send_deltas.push_back(QuicTime::Delta::Zero()); |
| bad_send_deltas.push_back(QuicTime::Delta::Infinite()); |
| bad_send_deltas.push_back(QuicTime::Delta::FromMicroseconds(-1000)); |
| |
| for (QuicTime::Delta bad_send_delta : bad_send_deltas) { |
| SCOPED_TRACE(Message() << "bad_send_delta = " |
| << bad_send_delta.ToMicroseconds()); |
| EXPECT_FALSE(rtt_stats_.UpdateRtt(bad_send_delta, QuicTime::Delta::Zero(), |
| QuicTime::Zero())); |
| EXPECT_EQ(initial_rtt, rtt_stats_.min_rtt()); |
| EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt()); |
| } |
| } |
| |
| TEST_F(RttStatsTest, ResetAfterConnectionMigrations) { |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(200), |
| QuicTime::Delta::FromMilliseconds(0), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.min_rtt()); |
| |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(300), |
| QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.min_rtt()); |
| |
| // Reset rtt stats on connection migrations. |
| rtt_stats_.OnConnectionMigration(); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.latest_rtt()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.smoothed_rtt()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.min_rtt()); |
| } |
| |
| TEST_F(RttStatsTest, StandardDeviationCaculatorTest1) { |
| // All samples are the same. |
| rtt_stats_.EnableStandardDeviationCalculation(); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(rtt_stats_.mean_deviation(), |
| rtt_stats_.GetStandardOrMeanDeviation()); |
| |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.GetStandardOrMeanDeviation()); |
| } |
| |
| TEST_F(RttStatsTest, StandardDeviationCaculatorTest2) { |
| // Small variance. |
| rtt_stats_.EnableStandardDeviationCalculation(); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(9), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(11), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_LT(QuicTime::Delta::FromMicroseconds(500), |
| rtt_stats_.GetStandardOrMeanDeviation()); |
| EXPECT_GT(QuicTime::Delta::FromMilliseconds(1), |
| rtt_stats_.GetStandardOrMeanDeviation()); |
| } |
| |
| TEST_F(RttStatsTest, StandardDeviationCaculatorTest3) { |
| // Some variance. |
| rtt_stats_.EnableStandardDeviationCalculation(); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(50), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(100), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(50), |
| QuicTime::Delta::Zero(), QuicTime::Zero()); |
| EXPECT_APPROX_EQ(rtt_stats_.mean_deviation(), |
| rtt_stats_.GetStandardOrMeanDeviation(), 0.25f); |
| } |
| |
| } // namespace test |
| } // namespace quic |