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// 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 "net/quic/congestion_control/rtt_stats.h"
#include <vector>
#include "base/logging.h"
#include "base/test/mock_log.h"
#include "net/quic/quic_flags.h"
#include "net/quic/test_tools/rtt_stats_peer.h"
#include "testing/gtest/include/gtest/gtest.h"
using logging::LOG_WARNING;
using std::vector;
using testing::HasSubstr;
using testing::Message;
using testing::_;
namespace net {
namespace test {
class RttStatsTest : public ::testing::Test {
protected:
RttStats rtt_stats_;
};
TEST_F(RttStatsTest, DefaultsBeforeUpdate) {
EXPECT_LT(0u, rtt_stats_.initial_rtt_us());
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 corrected for in Smoothed 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());
// Verify that effective RTT of zero does not change Smoothed RTT.
rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(200),
QuicTime::Delta::FromMilliseconds(200),
QuicTime::Zero());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), rtt_stats_.latest_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200), 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::FromMilliseconds(200), rtt_stats_.smoothed_rtt());
}
TEST_F(RttStatsTest, PreviousSmoothedRtt) {
FLAGS_quic_adaptive_loss_recovery = true;
// Verify that ack_delay is corrected for in Smoothed 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::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());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(200),
rtt_stats_.recent_min_rtt());
rtt_stats_.UpdateRtt(
QuicTime::Delta::FromMilliseconds(10), QuicTime::Delta::Zero(),
QuicTime::Zero().Add(QuicTime::Delta::FromMilliseconds(10)));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_min_rtt());
rtt_stats_.UpdateRtt(
QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(),
QuicTime::Zero().Add(QuicTime::Delta::FromMilliseconds(20)));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_min_rtt());
rtt_stats_.UpdateRtt(
QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(),
QuicTime::Zero().Add(QuicTime::Delta::FromMilliseconds(30)));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_min_rtt());
rtt_stats_.UpdateRtt(
QuicTime::Delta::FromMilliseconds(50), QuicTime::Delta::Zero(),
QuicTime::Zero().Add(QuicTime::Delta::FromMilliseconds(40)));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_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().Add(QuicTime::Delta::FromMilliseconds(50)));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(7), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(7), rtt_stats_.recent_min_rtt());
}
TEST_F(RttStatsTest, RecentMinRtt) {
rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(10),
QuicTime::Delta::Zero(), QuicTime::Zero());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_min_rtt());
rtt_stats_.SampleNewRecentMinRtt(4);
for (int i = 0; i < 3; ++i) {
rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(50),
QuicTime::Delta::Zero(), QuicTime::Zero());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10),
rtt_stats_.recent_min_rtt());
}
rtt_stats_.UpdateRtt(QuicTime::Delta::FromMilliseconds(50),
QuicTime::Delta::Zero(), QuicTime::Zero());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(50), rtt_stats_.recent_min_rtt());
}
TEST_F(RttStatsTest, WindowedRecentMinRtt) {
// Set the window to 99ms, so 25ms is more than a quarter rtt.
rtt_stats_.set_recent_min_rtt_window(QuicTime::Delta::FromMilliseconds(99));
QuicTime now = QuicTime::Zero();
QuicTime::Delta rtt_sample = QuicTime::Delta::FromMilliseconds(10);
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.recent_min_rtt());
// Gradually increase the rtt samples and ensure the recent_min_rtt starts
// rising.
for (int i = 0; i < 8; ++i) {
now = now.Add(QuicTime::Delta::FromMilliseconds(25));
rtt_sample = rtt_sample.Add(QuicTime::Delta::FromMilliseconds(10));
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(rtt_sample, RttStatsPeer::GetQuarterWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample.Subtract(QuicTime::Delta::FromMilliseconds(10)),
RttStatsPeer::GetHalfWindowRtt(&rtt_stats_));
if (i < 3) {
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10),
rtt_stats_.recent_min_rtt());
} else if (i < 5) {
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(30),
rtt_stats_.recent_min_rtt());
} else if (i < 7) {
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(50),
rtt_stats_.recent_min_rtt());
} else {
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(70),
rtt_stats_.recent_min_rtt());
}
}
// A new quarter rtt low sets that, but nothing else.
rtt_sample = rtt_sample.Subtract(QuicTime::Delta::FromMilliseconds(5));
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(rtt_sample, RttStatsPeer::GetQuarterWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample.Subtract(QuicTime::Delta::FromMilliseconds(5)),
RttStatsPeer::GetHalfWindowRtt(&rtt_stats_));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(70), rtt_stats_.recent_min_rtt());
// A new half rtt low sets that and the quarter rtt low.
rtt_sample = rtt_sample.Subtract(QuicTime::Delta::FromMilliseconds(15));
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(rtt_sample, RttStatsPeer::GetQuarterWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample, RttStatsPeer::GetHalfWindowRtt(&rtt_stats_));
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(70), rtt_stats_.recent_min_rtt());
// A new full window loss sets the recent_min_rtt, but not min_rtt.
rtt_sample = QuicTime::Delta::FromMilliseconds(65);
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(10), rtt_stats_.min_rtt());
EXPECT_EQ(rtt_sample, RttStatsPeer::GetQuarterWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample, RttStatsPeer::GetHalfWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample, rtt_stats_.recent_min_rtt());
// A new all time low sets both the min_rtt and the recent_min_rtt.
rtt_sample = QuicTime::Delta::FromMilliseconds(5);
rtt_stats_.UpdateRtt(rtt_sample, QuicTime::Delta::Zero(), now);
EXPECT_EQ(rtt_sample, rtt_stats_.min_rtt());
EXPECT_EQ(rtt_sample, RttStatsPeer::GetQuarterWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample, RttStatsPeer::GetHalfWindowRtt(&rtt_stats_));
EXPECT_EQ(rtt_sample, rtt_stats_.recent_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_.recent_min_rtt());
EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt());
EXPECT_EQ(initial_rtt.Multiply(0.5), rtt_stats_.mean_deviation());
// Update once with a 20ms RTT.
QuicTime::Delta doubled_rtt = initial_rtt.Multiply(2);
rtt_stats_.UpdateRtt(doubled_rtt, QuicTime::Delta::Zero(), QuicTime::Zero());
EXPECT_EQ(initial_rtt.Multiply(1.125), 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(initial_rtt.Multiply(0.875), 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 = initial_rtt.Multiply(0.5);
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) {
// Make sure we ignore bad RTTs.
base::test::MockLog log;
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_.recent_min_rtt());
EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt());
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));
log.StartCapturingLogs();
for (QuicTime::Delta bad_send_delta : bad_send_deltas) {
SCOPED_TRACE(Message() << "bad_send_delta = "
<< bad_send_delta.ToMicroseconds());
EXPECT_CALL(log, Log(LOG_WARNING, _, _, _, HasSubstr("Ignoring")));
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_.recent_min_rtt());
EXPECT_EQ(initial_rtt, rtt_stats_.smoothed_rtt());
}
}
TEST_F(RttStatsTest, ResetAfterConnectionMigrations) {
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(300), rtt_stats_.min_rtt());
EXPECT_EQ(QuicTime::Delta::FromMilliseconds(300),
rtt_stats_.recent_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());
EXPECT_EQ(QuicTime::Delta::Zero(), rtt_stats_.recent_min_rtt());
}
} // namespace test
} // namespace net
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