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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/alr_detector.h"
#include <cstdint>
#include "absl/types/optional.h"
#include "api/transport/field_trial_based_config.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/alr_experiment.h"
#include "test/field_trial.h"
#include "test/gtest.h"
namespace {
constexpr int kEstimatedBitrateBps = 300000;
} // namespace
namespace webrtc {
namespace {
class SimulateOutgoingTrafficIn {
public:
explicit SimulateOutgoingTrafficIn(AlrDetector* alr_detector,
int64_t* timestamp_ms)
: alr_detector_(alr_detector), timestamp_ms_(timestamp_ms) {
RTC_CHECK(alr_detector_);
}
SimulateOutgoingTrafficIn& ForTimeMs(int time_ms) {
interval_ms_ = time_ms;
ProduceTraffic();
return *this;
}
SimulateOutgoingTrafficIn& AtPercentOfEstimatedBitrate(int usage_percentage) {
usage_percentage_.emplace(usage_percentage);
ProduceTraffic();
return *this;
}
private:
void ProduceTraffic() {
if (!interval_ms_ || !usage_percentage_)
return;
const int kTimeStepMs = 10;
for (int t = 0; t < *interval_ms_; t += kTimeStepMs) {
*timestamp_ms_ += kTimeStepMs;
alr_detector_->OnBytesSent(kEstimatedBitrateBps * *usage_percentage_ *
kTimeStepMs / (8 * 100 * 1000),
*timestamp_ms_);
}
int remainder_ms = *interval_ms_ % kTimeStepMs;
if (remainder_ms > 0) {
*timestamp_ms_ += kTimeStepMs;
alr_detector_->OnBytesSent(kEstimatedBitrateBps * *usage_percentage_ *
remainder_ms / (8 * 100 * 1000),
*timestamp_ms_);
}
}
AlrDetector* const alr_detector_;
int64_t* timestamp_ms_;
absl::optional<int> interval_ms_;
absl::optional<int> usage_percentage_;
};
} // namespace
TEST(AlrDetectorTest, AlrDetection) {
FieldTrialBasedConfig field_trials;
int64_t timestamp_ms = 1000;
AlrDetector alr_detector(&field_trials);
alr_detector.SetEstimatedBitrate(kEstimatedBitrateBps);
// Start in non-ALR state.
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// Stay in non-ALR state when usage is close to 100%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1000)
.AtPercentOfEstimatedBitrate(90);
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// Verify that we ALR starts when bitrate drops below 20%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1500)
.AtPercentOfEstimatedBitrate(20);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
// Verify that ALR ends when usage is above 65%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(4000)
.AtPercentOfEstimatedBitrate(100);
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
}
TEST(AlrDetectorTest, ShortSpike) {
FieldTrialBasedConfig field_trials;
int64_t timestamp_ms = 1000;
AlrDetector alr_detector(&field_trials);
alr_detector.SetEstimatedBitrate(kEstimatedBitrateBps);
// Start in non-ALR state.
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// Verify that we ALR starts when bitrate drops below 20%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1000)
.AtPercentOfEstimatedBitrate(20);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
// Verify that we stay in ALR region even after a short bitrate spike.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(100)
.AtPercentOfEstimatedBitrate(150);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
// ALR ends when usage is above 65%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(3000)
.AtPercentOfEstimatedBitrate(100);
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
}
TEST(AlrDetectorTest, BandwidthEstimateChanges) {
FieldTrialBasedConfig field_trials;
int64_t timestamp_ms = 1000;
AlrDetector alr_detector(&field_trials);
alr_detector.SetEstimatedBitrate(kEstimatedBitrateBps);
// Start in non-ALR state.
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// ALR starts when bitrate drops below 20%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1000)
.AtPercentOfEstimatedBitrate(20);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
// When bandwidth estimate drops the detector should stay in ALR mode and quit
// it shortly afterwards as the sender continues sending the same amount of
// traffic. This is necessary to ensure that ProbeController can still react
// to the BWE drop by initiating a new probe.
alr_detector.SetEstimatedBitrate(kEstimatedBitrateBps / 5);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1000)
.AtPercentOfEstimatedBitrate(50);
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
}
TEST(AlrDetectorTest, ParseControlFieldTrial) {
webrtc::test::ScopedFieldTrials scoped_field_trial(
"WebRTC-ProbingScreenshareBwe/Control/");
absl::optional<AlrExperimentSettings> parsed_params =
AlrExperimentSettings::CreateFromFieldTrial(
FieldTrialBasedConfig(), "WebRTC-ProbingScreenshareBwe");
EXPECT_FALSE(static_cast<bool>(parsed_params));
}
TEST(AlrDetectorTest, ParseActiveFieldTrial) {
webrtc::test::ScopedFieldTrials scoped_field_trial(
"WebRTC-ProbingScreenshareBwe/1.1,2875,85,20,-20,1/");
absl::optional<AlrExperimentSettings> parsed_params =
AlrExperimentSettings::CreateFromFieldTrial(
FieldTrialBasedConfig(), "WebRTC-ProbingScreenshareBwe");
ASSERT_TRUE(static_cast<bool>(parsed_params));
EXPECT_EQ(1.1f, parsed_params->pacing_factor);
EXPECT_EQ(2875, parsed_params->max_paced_queue_time);
EXPECT_EQ(85, parsed_params->alr_bandwidth_usage_percent);
EXPECT_EQ(20, parsed_params->alr_start_budget_level_percent);
EXPECT_EQ(-20, parsed_params->alr_stop_budget_level_percent);
EXPECT_EQ(1, parsed_params->group_id);
}
TEST(AlrDetectorTest, ParseAlrSpecificFieldTrial) {
webrtc::test::ScopedFieldTrials scoped_field_trial(
"WebRTC-AlrDetectorParameters/"
"bw_usage:90%,start:0%,stop:-10%/");
FieldTrialBasedConfig field_trials;
AlrDetector alr_detector(&field_trials);
int64_t timestamp_ms = 1000;
alr_detector.SetEstimatedBitrate(kEstimatedBitrateBps);
// Start in non-ALR state.
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// ALR does not start at 100% utilization.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(1000)
.AtPercentOfEstimatedBitrate(100);
EXPECT_FALSE(alr_detector.GetApplicationLimitedRegionStartTime());
// ALR does start at 85% utilization.
// Overused 10% above so it should take about 2s to reach a budget level of
// 0%.
SimulateOutgoingTrafficIn(&alr_detector, ×tamp_ms)
.ForTimeMs(2100)
.AtPercentOfEstimatedBitrate(85);
EXPECT_TRUE(alr_detector.GetApplicationLimitedRegionStartTime());
}
} // namespace webrtc
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