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/*
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/congestion_controller/goog_cc/probe_controller.h"
#include <memory>
#include "api/transport/field_trial_based_config.h"
#include "api/transport/network_types.h"
#include "api/units/data_rate.h"
#include "api/units/timestamp.h"
#include "logging/rtc_event_log/mock/mock_rtc_event_log.h"
#include "rtc_base/logging.h"
#include "system_wrappers/include/clock.h"
#include "test/field_trial.h"
#include "test/gmock.h"
#include "test/gtest.h"
using ::testing::_;
using ::testing::AtLeast;
using ::testing::Field;
using ::testing::Matcher;
using ::testing::NiceMock;
using ::testing::Return;
namespace webrtc {
namespace test {
namespace {
constexpr int kMinBitrateBps = 100;
constexpr int kStartBitrateBps = 300;
constexpr int kMaxBitrateBps = 10000;
constexpr int kExponentialProbingTimeoutMs = 5000;
constexpr int kAlrProbeInterval = 5000;
constexpr int kAlrEndedTimeoutMs = 3000;
constexpr int kBitrateDropTimeoutMs = 5000;
} // namespace
class ProbeControllerTest : public ::testing::Test {
protected:
ProbeControllerTest() : clock_(100000000L) {
probe_controller_.reset(
new ProbeController(&field_trial_config_, &mock_rtc_event_log));
}
~ProbeControllerTest() override {}
std::vector<ProbeClusterConfig> SetNetworkAvailable(bool available) {
NetworkAvailability msg;
msg.at_time = Timestamp::ms(NowMs());
msg.network_available = available;
return probe_controller_->OnNetworkAvailability(msg);
}
int64_t NowMs() { return clock_.TimeInMilliseconds(); }
FieldTrialBasedConfig field_trial_config_;
SimulatedClock clock_;
NiceMock<MockRtcEventLog> mock_rtc_event_log;
std::unique_ptr<ProbeController> probe_controller_;
};
TEST_F(ProbeControllerTest, InitiatesProbingAtStart) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_GE(probes.size(), 2u);
}
TEST_F(ProbeControllerTest, ProbeOnlyWhenNetworkIsUp) {
SetNetworkAvailable(false);
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 0u);
probes = SetNetworkAvailable(true);
EXPECT_GE(probes.size(), 2u);
}
TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncrease) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
// Long enough to time out exponential probing.
clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps + 100, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
}
TEST_F(ProbeControllerTest, ProbesOnMaxBitrateIncreaseOnlyWhenInAlr) {
probe_controller_.reset(
new ProbeController(&field_trial_config_, &mock_rtc_event_log));
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps - 1, NowMs());
// Wait long enough to time out exponential probing.
clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 0u);
// Probe when in alr.
probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 1,
NowMs());
EXPECT_EQ(probes.size(), 2u);
// Do not probe when not in alr.
probe_controller_->SetAlrStartTimeMs(absl::nullopt);
probes = probe_controller_->OnMaxTotalAllocatedBitrate(kMaxBitrateBps + 2,
NowMs());
EXPECT_TRUE(probes.empty());
}
TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncreaseAtMaxBitrate) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
// Long enough to time out exponential probing.
clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
probes = probe_controller_->SetEstimatedBitrate(kStartBitrateBps, NowMs());
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(kMaxBitrateBps, NowMs());
probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps + 100, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), kMaxBitrateBps + 100);
}
TEST_F(ProbeControllerTest, TestExponentialProbing) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
// Repeated probe should only be sent when estimated bitrate climbs above
// 0.7 * 6 * kStartBitrateBps = 1260.
probes = probe_controller_->SetEstimatedBitrate(1000, NowMs());
EXPECT_EQ(probes.size(), 0u);
probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * 1800);
}
TEST_F(ProbeControllerTest, TestExponentialProbingTimeout) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
// Advance far enough to cause a time out in waiting for probing result.
clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(1800, NowMs());
EXPECT_EQ(probes.size(), 0u);
}
TEST_F(ProbeControllerTest, RequestProbeInAlr) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_GE(probes.size(), 2u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
probes = probe_controller_->RequestProbe(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
}
TEST_F(ProbeControllerTest, RequestProbeWhenAlrEndedRecently) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 2u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
probe_controller_->SetAlrStartTimeMs(absl::nullopt);
clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs - 1);
probes = probe_controller_->RequestProbe(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 0.85 * 500);
}
TEST_F(ProbeControllerTest, RequestProbeWhenAlrNotEndedRecently) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 2u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
probe_controller_->SetAlrStartTimeMs(absl::nullopt);
clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
probe_controller_->SetAlrEndedTimeMs(clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(kAlrEndedTimeoutMs + 1);
probes = probe_controller_->RequestProbe(NowMs());
EXPECT_EQ(probes.size(), 0u);
}
TEST_F(ProbeControllerTest, RequestProbeWhenBweDropNotRecent) {
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 2u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
probe_controller_->SetAlrStartTimeMs(clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(250, NowMs());
clock_.AdvanceTimeMilliseconds(kBitrateDropTimeoutMs + 1);
probes = probe_controller_->RequestProbe(NowMs());
EXPECT_EQ(probes.size(), 0u);
}
TEST_F(ProbeControllerTest, PeriodicProbing) {
probe_controller_->EnablePeriodicAlrProbing(true);
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 2u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
int64_t start_time = clock_.TimeInMilliseconds();
// Expect the controller to send a new probe after 5s has passed.
probe_controller_->SetAlrStartTimeMs(start_time);
clock_.AdvanceTimeMilliseconds(5000);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 1000);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
// The following probe should be sent at 10s into ALR.
probe_controller_->SetAlrStartTimeMs(start_time);
clock_.AdvanceTimeMilliseconds(4000);
probes = probe_controller_->Process(NowMs());
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
EXPECT_EQ(probes.size(), 0u);
probe_controller_->SetAlrStartTimeMs(start_time);
clock_.AdvanceTimeMilliseconds(1000);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 1u);
probes = probe_controller_->SetEstimatedBitrate(500, NowMs());
EXPECT_EQ(probes.size(), 0u);
}
TEST_F(ProbeControllerTest, PeriodicProbingAfterReset) {
probe_controller_.reset(
new ProbeController(&field_trial_config_, &mock_rtc_event_log));
int64_t alr_start_time = clock_.TimeInMilliseconds();
probe_controller_->SetAlrStartTimeMs(alr_start_time);
probe_controller_->EnablePeriodicAlrProbing(true);
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
probe_controller_->Reset(NowMs());
clock_.AdvanceTimeMilliseconds(10000);
probes = probe_controller_->Process(NowMs());
// Since bitrates are not yet set, no probe is sent event though we are in ALR
// mode.
EXPECT_EQ(probes.size(), 0u);
probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
kMaxBitrateBps, NowMs());
EXPECT_EQ(probes.size(), 2u);
// Make sure we use |kStartBitrateBps| as the estimated bitrate
// until SetEstimatedBitrate is called with an updated estimate.
clock_.AdvanceTimeMilliseconds(10000);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), kStartBitrateBps * 2);
}
TEST_F(ProbeControllerTest, TestExponentialProbingOverflow) {
const int64_t kMbpsMultiplier = 1000000;
auto probes = probe_controller_->SetBitrates(
kMinBitrateBps, 10 * kMbpsMultiplier, 100 * kMbpsMultiplier, NowMs());
// Verify that probe bitrate is capped at the specified max bitrate.
probes =
probe_controller_->SetEstimatedBitrate(60 * kMbpsMultiplier, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 100 * kMbpsMultiplier);
// Verify that repeated probes aren't sent.
probes =
probe_controller_->SetEstimatedBitrate(100 * kMbpsMultiplier, NowMs());
EXPECT_EQ(probes.size(), 0u);
}
TEST_F(ProbeControllerTest, TestAllocatedBitrateCap) {
const int64_t kMbpsMultiplier = 1000000;
const int64_t kMaxBitrateBps = 100 * kMbpsMultiplier;
auto probes = probe_controller_->SetBitrates(
kMinBitrateBps, 10 * kMbpsMultiplier, kMaxBitrateBps, NowMs());
// Configure ALR for periodic probing.
probe_controller_->EnablePeriodicAlrProbing(true);
int64_t alr_start_time = clock_.TimeInMilliseconds();
probe_controller_->SetAlrStartTimeMs(alr_start_time);
int64_t estimated_bitrate_bps = kMaxBitrateBps / 10;
probes =
probe_controller_->SetEstimatedBitrate(estimated_bitrate_bps, NowMs());
// Set a max allocated bitrate below the current estimate.
int64_t max_allocated_bps = estimated_bitrate_bps - 1 * kMbpsMultiplier;
probes =
probe_controller_->OnMaxTotalAllocatedBitrate(max_allocated_bps, NowMs());
EXPECT_TRUE(probes.empty()); // No probe since lower than current max.
// Probes such as ALR capped at 2x the max allocation limit.
clock_.AdvanceTimeMilliseconds(5000);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 2 * max_allocated_bps);
// Remove allocation limit.
EXPECT_TRUE(
probe_controller_->OnMaxTotalAllocatedBitrate(0, NowMs()).empty());
clock_.AdvanceTimeMilliseconds(5000);
probes = probe_controller_->Process(NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), estimated_bitrate_bps * 2);
}
TEST_F(ProbeControllerTest, ConfigurableProbingFieldTrial) {
test::ScopedFieldTrials trials(
"WebRTC-Bwe-ProbingConfiguration/"
"p1:2,p2:5,step_size:3,further_probe_threshold:0.8,"
"alloc_p1:2,alloc_p2/");
probe_controller_.reset(
new ProbeController(&field_trial_config_, &mock_rtc_event_log));
auto probes = probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
5000000, NowMs());
EXPECT_EQ(probes.size(), 2u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 600);
EXPECT_EQ(probes[1].target_data_rate.bps(), 1500);
// Repeated probe should only be sent when estimated bitrate climbs above
// 0.8 * 5 * kStartBitrateBps = 1200.
probes = probe_controller_->SetEstimatedBitrate(1100, NowMs());
EXPECT_EQ(probes.size(), 0u);
probes = probe_controller_->SetEstimatedBitrate(1250, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 3 * 1250);
clock_.AdvanceTimeMilliseconds(5000);
probes = probe_controller_->Process(NowMs());
probe_controller_->SetAlrStartTimeMs(NowMs());
probes = probe_controller_->OnMaxTotalAllocatedBitrate(200000, NowMs());
EXPECT_EQ(probes.size(), 1u);
EXPECT_EQ(probes[0].target_data_rate.bps(), 400000);
}
} // namespace test
} // namespace webrtc