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eb48799ec5048459b2b5e00b6d940ddcf76c72d9
platform-external-webrtc/modules/pacing/pacing_controller_unittest.cc
Erik Språng eb48799ec5 Prepares PacingController for scheduled send tasks. 
This CL is in preparation for a dynamic (possible TaskQueue-driven)
pacer that instead of processing blindly every 5ms, posts delayed
tasks to be executed when it is actually time to send packs.

This means we need the pacing controller to be able to figure out when
those execution times shall be, and be able to correctly update budget
levels as IntervalBudget only works correctly with periodic processing.

Bug: webrtc:10809
Change-Id: Idd12acaabfb24cc2e6bcc589aac206cd04beb6e4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158790
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29800}
2019-11-14 13:53:56 +00:00

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/*
* Copyright (c) 2019 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/pacing/pacing_controller.h"
#include <algorithm>
#include <list>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "api/units/data_rate.h"
#include "modules/pacing/packet_router.h"
#include "system_wrappers/include/clock.h"
#include "test/field_trial.h"
#include "test/gmock.h"
#include "test/gtest.h"
using ::testing::_;
using ::testing::Field;
using ::testing::Pointee;
using ::testing::Property;
using ::testing::Return;
namespace webrtc {
namespace test {
namespace {
constexpr DataRate kFirstClusterRate = DataRate::KilobitsPerSec<900>();
constexpr DataRate kSecondClusterRate = DataRate::KilobitsPerSec<1800>();
// The error stems from truncating the time interval of probe packets to integer
// values. This results in probing slightly higher than the target bitrate.
// For 1.8 Mbps, this comes to be about 120 kbps with 1200 probe packets.
constexpr DataRate kProbingErrorMargin = DataRate::KilobitsPerSec<150>();
const float kPaceMultiplier = 2.5f;
constexpr uint32_t kAudioSsrc = 12345;
constexpr uint32_t kVideoSsrc = 234565;
constexpr uint32_t kVideoRtxSsrc = 34567;
constexpr uint32_t kFlexFecSsrc = 45678;
constexpr DataRate kTargetRate = DataRate::KilobitsPerSec<800>();
std::unique_ptr<RtpPacketToSend> BuildPacket(RtpPacketToSend::Type type,
uint32_t ssrc,
uint16_t sequence_number,
int64_t capture_time_ms,
size_t size) {
auto packet = std::make_unique<RtpPacketToSend>(nullptr);
packet->set_packet_type(type);
packet->SetSsrc(ssrc);
packet->SetSequenceNumber(sequence_number);
packet->set_capture_time_ms(capture_time_ms);
packet->SetPayloadSize(size);
return packet;
}
} // namespace
// Mock callback proxy, where both new and old api redirects to common mock
// methods that focus on core aspects.
class MockPacingControllerCallback : public PacingController::PacketSender {
public:
void SendRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& cluster_info) override {
SendPacket(packet->Ssrc(), packet->SequenceNumber(),
packet->capture_time_ms(),
packet->packet_type() == RtpPacketToSend::Type::kRetransmission,
packet->packet_type() == RtpPacketToSend::Type::kPadding);
}
std::vector<std::unique_ptr<RtpPacketToSend>> GeneratePadding(
DataSize target_size) override {
std::vector<std::unique_ptr<RtpPacketToSend>> ret;
size_t padding_size = SendPadding(target_size.bytes());
if (padding_size > 0) {
auto packet = std::make_unique<RtpPacketToSend>(nullptr);
packet->SetPayloadSize(padding_size);
packet->set_packet_type(RtpPacketToSend::Type::kPadding);
ret.emplace_back(std::move(packet));
}
return ret;
}
MOCK_METHOD5(SendPacket,
void(uint32_t ssrc,
uint16_t sequence_number,
int64_t capture_timestamp,
bool retransmission,
bool padding));
MOCK_METHOD1(SendPadding, size_t(size_t target_size));
};
// Mock callback implementing the raw api.
class MockPacketSender : public PacingController::PacketSender {
public:
MOCK_METHOD2(SendRtpPacket,
void(std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& cluster_info));
MOCK_METHOD1(
GeneratePadding,
std::vector<std::unique_ptr<RtpPacketToSend>>(DataSize target_size));
};
class PacingControllerPadding : public PacingController::PacketSender {
public:
static const size_t kPaddingPacketSize = 224;
PacingControllerPadding() : padding_sent_(0), total_bytes_sent_(0) {}
void SendRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& pacing_info) override {
total_bytes_sent_ += packet->payload_size();
}
std::vector<std::unique_ptr<RtpPacketToSend>> GeneratePadding(
DataSize target_size) override {
size_t num_packets =
(target_size.bytes() + kPaddingPacketSize - 1) / kPaddingPacketSize;
std::vector<std::unique_ptr<RtpPacketToSend>> packets;
for (size_t i = 0; i < num_packets; ++i) {
packets.emplace_back(std::make_unique<RtpPacketToSend>(nullptr));
packets.back()->SetPadding(kPaddingPacketSize);
packets.back()->set_packet_type(RtpPacketToSend::Type::kPadding);
padding_sent_ += kPaddingPacketSize;
}
return packets;
}
size_t padding_sent() { return padding_sent_; }
size_t total_bytes_sent() { return total_bytes_sent_; }
private:
size_t padding_sent_;
size_t total_bytes_sent_;
};
class PacingControllerProbing : public PacingController::PacketSender {
public:
PacingControllerProbing() : packets_sent_(0), padding_sent_(0) {}
void SendRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& pacing_info) override {
if (packet->packet_type() != RtpPacketToSend::Type::kPadding) {
++packets_sent_;
}
}
std::vector<std::unique_ptr<RtpPacketToSend>> GeneratePadding(
DataSize target_size) override {
// From RTPSender:
// Max in the RFC 3550 is 255 bytes, we limit it to be modulus 32 for SRTP.
const DataSize kMaxPadding = DataSize::bytes(224);
std::vector<std::unique_ptr<RtpPacketToSend>> packets;
while (target_size > DataSize::Zero()) {
DataSize padding_size = std::min(kMaxPadding, target_size);
packets.emplace_back(std::make_unique<RtpPacketToSend>(nullptr));
packets.back()->SetPadding(padding_size.bytes());
packets.back()->set_packet_type(RtpPacketToSend::Type::kPadding);
padding_sent_ += padding_size.bytes();
target_size -= padding_size;
}
return packets;
}
int packets_sent() const { return packets_sent_; }
int padding_sent() const { return padding_sent_; }
private:
int packets_sent_;
int padding_sent_;
};
class PacingControllerTest
: public ::testing::TestWithParam<PacingController::ProcessMode> {
protected:
PacingControllerTest() : clock_(123456) {
srand(0);
// Need to initialize PacingController after we initialize clock.
pacer_ = std::make_unique<PacingController>(&clock_, &callback_, nullptr,
nullptr, GetParam());
Init();
}
bool PeriodicProcess() const {
return GetParam() == PacingController::ProcessMode::kPeriodic;
}
void Init() {
pacer_->CreateProbeCluster(kFirstClusterRate, /*cluster_id=*/0);
pacer_->CreateProbeCluster(kSecondClusterRate, /*cluster_id=*/1);
// Default to bitrate probing disabled for testing purposes. Probing tests
// have to enable probing, either by creating a new PacingController
// instance or by calling SetProbingEnabled(true).
pacer_->SetProbingEnabled(false);
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, DataRate::Zero());
clock_.AdvanceTime(TimeUntilNextProcess());
}
void Send(RtpPacketToSend::Type type,
uint32_t ssrc,
uint16_t sequence_number,
int64_t capture_time_ms,
size_t size) {
pacer_->EnqueuePacket(
BuildPacket(type, ssrc, sequence_number, capture_time_ms, size));
}
void SendAndExpectPacket(RtpPacketToSend::Type type,
uint32_t ssrc,
uint16_t sequence_number,
int64_t capture_time_ms,
size_t size) {
Send(type, ssrc, sequence_number, capture_time_ms, size);
EXPECT_CALL(
callback_,
SendPacket(ssrc, sequence_number, capture_time_ms,
type == RtpPacketToSend::Type::kRetransmission, false))
.Times(1);
}
std::unique_ptr<RtpPacketToSend> BuildRtpPacket(RtpPacketToSend::Type type) {
auto packet = std::make_unique<RtpPacketToSend>(nullptr);
packet->set_packet_type(type);
switch (type) {
case RtpPacketToSend::Type::kAudio:
packet->SetSsrc(kAudioSsrc);
break;
case RtpPacketToSend::Type::kVideo:
packet->SetSsrc(kVideoSsrc);
break;
case RtpPacketToSend::Type::kRetransmission:
case RtpPacketToSend::Type::kPadding:
packet->SetSsrc(kVideoRtxSsrc);
break;
case RtpPacketToSend::Type::kForwardErrorCorrection:
packet->SetSsrc(kFlexFecSsrc);
break;
}
packet->SetPayloadSize(234);
return packet;
}
TimeDelta TimeUntilNextProcess() {
Timestamp now = clock_.CurrentTime();
return std::max(pacer_->NextSendTime() - now, TimeDelta::Zero());
}
void AdvanceTimeAndProcess() {
Timestamp now = clock_.CurrentTime();
Timestamp next_send_time = pacer_->NextSendTime();
clock_.AdvanceTime(std::max(TimeDelta::Zero(), next_send_time - now));
pacer_->ProcessPackets();
}
void ConsumeInitialBudget() {
const uint32_t kSsrc = 54321;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = clock_.TimeInMilliseconds();
const size_t kPacketSize = 250;
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
// Due to the multiplicative factor we can send 5 packets during a send
// interval. (network capacity * multiplier / (8 bits per byte *
// (packet size * #send intervals per second)
const size_t packets_to_send_per_interval =
kTargetRate.bps() * kPaceMultiplier / (8 * kPacketSize * 200);
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, kSsrc,
sequence_number++, capture_time_ms, kPacketSize);
}
while (pacer_->QueueSizePackets() > 0) {
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
}
SimulatedClock clock_;
MockPacingControllerCallback callback_;
std::unique_ptr<PacingController> pacer_;
};
class PacingControllerFieldTrialTest
: public ::testing::TestWithParam<PacingController::ProcessMode> {
protected:
struct MediaStream {
const RtpPacketToSend::Type type;
const uint32_t ssrc;
const size_t packet_size;
uint16_t seq_num;
};
const int kProcessIntervalsPerSecond = 1000 / 5;
PacingControllerFieldTrialTest() : clock_(123456) {}
void InsertPacket(PacingController* pacer, MediaStream* stream) {
pacer->EnqueuePacket(
BuildPacket(stream->type, stream->ssrc, stream->seq_num++,
clock_.TimeInMilliseconds(), stream->packet_size));
}
void ProcessNext(PacingController* pacer) {
if (GetParam() == PacingController::ProcessMode::kPeriodic) {
TimeDelta process_interval = TimeDelta::ms(5);
clock_.AdvanceTime(process_interval);
pacer->ProcessPackets();
return;
}
Timestamp now = clock_.CurrentTime();
Timestamp next_send_time = pacer->NextSendTime();
TimeDelta wait_time = std::max(TimeDelta::Zero(), next_send_time - now);
clock_.AdvanceTime(wait_time);
pacer->ProcessPackets();
}
MediaStream audio{/*type*/ RtpPacketToSend::Type::kAudio,
/*ssrc*/ 3333, /*packet_size*/ 100, /*seq_num*/ 1000};
MediaStream video{/*type*/ RtpPacketToSend::Type::kVideo,
/*ssrc*/ 4444, /*packet_size*/ 1000, /*seq_num*/ 1000};
SimulatedClock clock_;
MockPacingControllerCallback callback_;
};
TEST_P(PacingControllerFieldTrialTest, DefaultNoPaddingInSilence) {
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
pacer.SetPacingRates(kTargetRate, DataRate::Zero());
// Video packet to reset last send time and provide padding data.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(1);
clock_.AdvanceTimeMilliseconds(5);
pacer.ProcessPackets();
EXPECT_CALL(callback_, SendPadding).Times(0);
// Waiting 500 ms should not trigger sending of padding.
clock_.AdvanceTimeMilliseconds(500);
pacer.ProcessPackets();
}
TEST_P(PacingControllerFieldTrialTest, PaddingInSilenceWithTrial) {
ScopedFieldTrials trial("WebRTC-Pacer-PadInSilence/Enabled/");
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
pacer.SetPacingRates(kTargetRate, DataRate::Zero());
// Video packet to reset last send time and provide padding data.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(2);
clock_.AdvanceTimeMilliseconds(5);
pacer.ProcessPackets();
EXPECT_CALL(callback_, SendPadding).WillOnce(Return(1000));
// Waiting 500 ms should trigger sending of padding.
clock_.AdvanceTimeMilliseconds(500);
pacer.ProcessPackets();
}
TEST_P(PacingControllerFieldTrialTest, DefaultCongestionWindowAffectsAudio) {
EXPECT_CALL(callback_, SendPadding).Times(0);
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
pacer.SetPacingRates(DataRate::kbps(10000), DataRate::Zero());
pacer.SetCongestionWindow(DataSize::bytes(video.packet_size - 100));
pacer.UpdateOutstandingData(DataSize::Zero());
// Video packet fills congestion window.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
// Audio packet blocked due to congestion.
InsertPacket(&pacer, &audio);
EXPECT_CALL(callback_, SendPacket).Times(0);
if (GetParam() == PacingController::ProcessMode::kDynamic) {
// Without interval budget we'll forward time to where we send keep-alive.
EXPECT_CALL(callback_, SendPadding(1)).Times(2);
}
ProcessNext(&pacer);
ProcessNext(&pacer);
// Audio packet unblocked when congestion window clear.
::testing::Mock::VerifyAndClearExpectations(&callback_);
pacer.UpdateOutstandingData(DataSize::Zero());
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
}
TEST_P(PacingControllerFieldTrialTest,
CongestionWindowDoesNotAffectAudioInTrial) {
ScopedFieldTrials trial("WebRTC-Pacer-BlockAudio/Disabled/");
EXPECT_CALL(callback_, SendPadding).Times(0);
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
pacer.SetPacingRates(DataRate::bps(10000000), DataRate::Zero());
pacer.SetCongestionWindow(DataSize::bytes(800));
pacer.UpdateOutstandingData(DataSize::Zero());
// Video packet fills congestion window.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
// Audio not blocked due to congestion.
InsertPacket(&pacer, &audio);
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
}
TEST_P(PacingControllerFieldTrialTest, DefaultBudgetAffectsAudio) {
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
DataRate pacing_rate =
DataRate::bps(video.packet_size / 3 * 8 * kProcessIntervalsPerSecond);
pacer.SetPacingRates(pacing_rate, DataRate::Zero());
// Video fills budget for following process periods.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
// Audio packet blocked due to budget limit.
InsertPacket(&pacer, &audio);
Timestamp wait_start_time = clock_.CurrentTime();
Timestamp wait_end_time = Timestamp::MinusInfinity();
EXPECT_CALL(callback_, SendPacket)
.WillOnce([&](uint32_t ssrc, uint16_t sequence_number,
int64_t capture_timestamp, bool retransmission,
bool padding) { wait_end_time = clock_.CurrentTime(); });
while (!wait_end_time.IsFinite()) {
ProcessNext(&pacer);
}
const TimeDelta expected_wait_time =
DataSize::bytes(video.packet_size) / pacing_rate;
// Verify delay is near expectation, within timing margin.
EXPECT_LT(((wait_end_time - wait_start_time) - expected_wait_time).Abs(),
GetParam() == PacingController::ProcessMode::kPeriodic
? TimeDelta::ms(5)
: PacingController::kMinSleepTime);
}
TEST_P(PacingControllerFieldTrialTest, BudgetDoesNotAffectAudioInTrial) {
ScopedFieldTrials trial("WebRTC-Pacer-BlockAudio/Disabled/");
EXPECT_CALL(callback_, SendPadding).Times(0);
PacingController pacer(&clock_, &callback_, nullptr, nullptr, GetParam());
pacer.SetPacingRates(
DataRate::bps(video.packet_size / 3 * 8 * kProcessIntervalsPerSecond),
DataRate::Zero());
// Video fills budget for following process periods.
InsertPacket(&pacer, &video);
EXPECT_CALL(callback_, SendPacket).Times(1);
ProcessNext(&pacer);
// Audio packet not blocked due to budget limit.
EXPECT_CALL(callback_, SendPacket).Times(1);
InsertPacket(&pacer, &audio);
ProcessNext(&pacer);
}
INSTANTIATE_TEST_SUITE_P(WithAndWithoutIntervalBudget,
PacingControllerFieldTrialTest,
::testing::Values(false, true));
TEST_P(PacingControllerTest, FirstSentPacketTimeIsSet) {
uint16_t sequence_number = 1234;
const uint32_t kSsrc = 12345;
const size_t kSizeBytes = 250;
const size_t kPacketToSend = 3;
const Timestamp kStartTime = clock_.CurrentTime();
// No packet sent.
EXPECT_FALSE(pacer_->FirstSentPacketTime().has_value());
for (size_t i = 0; i < kPacketToSend; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, kSsrc, sequence_number++,
clock_.TimeInMilliseconds(), kSizeBytes);
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
}
EXPECT_EQ(kStartTime, pacer_->FirstSentPacketTime());
}
TEST_P(PacingControllerTest, QueuePacket) {
if (!PeriodicProcess()) {
// This test checks behavior applicable only when using interval budget.
return;
}
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
// Due to the multiplicative factor we can send 5 packets during a 5ms send
// interval. (network capacity * multiplier / (8 bits per byte *
// (packet size * #send intervals per second)
const size_t kPacketsToSend =
kTargetRate.bps() * kPaceMultiplier / (8 * 250 * 200);
for (size_t i = 0; i < kPacketsToSend; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), 250);
}
EXPECT_CALL(callback_, SendPadding).Times(0);
// Enqueue one extra packet.
int64_t queued_packet_timestamp = clock_.TimeInMilliseconds();
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number,
queued_packet_timestamp, 250);
EXPECT_EQ(kPacketsToSend + 1, pacer_->QueueSizePackets());
// The first kPacketsToSend packets will be sent with budget from the
// initial 5ms interval.
pacer_->ProcessPackets();
EXPECT_EQ(1u, pacer_->QueueSizePackets());
// Advance time to next interval, make sure the last packet is sent.
clock_.AdvanceTimeMilliseconds(5);
EXPECT_CALL(callback_, SendPacket(ssrc, sequence_number++,
queued_packet_timestamp, false, false))
.Times(1);
pacer_->ProcessPackets();
sequence_number++;
EXPECT_EQ(0u, pacer_->QueueSizePackets());
// We can send packets_to_send -1 packets of size 250 during the current
// interval since one packet has already been sent.
for (size_t i = 0; i < kPacketsToSend - 1; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), 250);
}
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), 250);
EXPECT_EQ(kPacketsToSend, pacer_->QueueSizePackets());
pacer_->ProcessPackets();
EXPECT_EQ(1u, pacer_->QueueSizePackets());
}
TEST_P(PacingControllerTest, QueueAndPacePackets) {
if (PeriodicProcess()) {
// This test checks behavior when not using interval budget.
return;
}
const uint32_t kSsrc = 12345;
uint16_t sequence_number = 1234;
const DataSize kPackeSize = DataSize::bytes(250);
const TimeDelta kSendInterval = TimeDelta::ms(5);
// Due to the multiplicative factor we can send 5 packets during a 5ms send
// interval. (send interval * network capacity * multiplier / packet size)
const size_t kPacketsToSend = (kSendInterval * kTargetRate).bytes() *
kPaceMultiplier / kPackeSize.bytes();
for (size_t i = 0; i < kPacketsToSend; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, kSsrc, sequence_number++,
clock_.TimeInMilliseconds(), kPackeSize.bytes());
}
EXPECT_CALL(callback_, SendPadding).Times(0);
// Enqueue one extra packet.
int64_t queued_packet_timestamp = clock_.TimeInMilliseconds();
Send(RtpPacketToSend::Type::kVideo, kSsrc, sequence_number,
queued_packet_timestamp, kPackeSize.bytes());
EXPECT_EQ(kPacketsToSend + 1, pacer_->QueueSizePackets());
// Send packets until the initial kPacketsToSend packets are done.
Timestamp start_time = clock_.CurrentTime();
while (pacer_->QueueSizePackets() > 1) {
AdvanceTimeAndProcess();
}
EXPECT_LT(clock_.CurrentTime() - start_time, kSendInterval);
// Proceed till last packet can be sent.
EXPECT_CALL(callback_, SendPacket(kSsrc, sequence_number,
queued_packet_timestamp, false, false))
.Times(1);
AdvanceTimeAndProcess();
EXPECT_GE(clock_.CurrentTime() - start_time, kSendInterval);
EXPECT_EQ(pacer_->QueueSizePackets(), 0u);
}
TEST_P(PacingControllerTest, PaceQueuedPackets) {
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
const size_t kPacketSize = 250;
// Due to the multiplicative factor we can send 5 packets during a send
// interval. (network capacity * multiplier / (8 bits per byte *
// (packet size * #send intervals per second)
const size_t packets_to_send_per_interval =
kTargetRate.bps() * kPaceMultiplier / (8 * kPacketSize * 200);
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
for (size_t j = 0; j < packets_to_send_per_interval * 10; ++j) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
EXPECT_EQ(packets_to_send_per_interval + packets_to_send_per_interval * 10,
pacer_->QueueSizePackets());
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > packets_to_send_per_interval * 10) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(pacer_->QueueSizePackets(), packets_to_send_per_interval * 10);
EXPECT_CALL(callback_, SendPadding).Times(0);
EXPECT_CALL(callback_, SendPacket(ssrc, _, _, false, false))
.Times(pacer_->QueueSizePackets());
const TimeDelta expected_pace_time =
DataSize::bytes(pacer_->QueueSizePackets() * kPacketSize) /
(kPaceMultiplier * kTargetRate);
Timestamp start_time = clock_.CurrentTime();
while (pacer_->QueueSizePackets() > 0) {
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
const TimeDelta actual_pace_time = clock_.CurrentTime() - start_time;
EXPECT_LT(
(actual_pace_time - expected_pace_time).Abs(),
PeriodicProcess() ? TimeDelta::ms(5) : PacingController::kMinSleepTime);
EXPECT_EQ(0u, pacer_->QueueSizePackets());
clock_.AdvanceTime(TimeUntilNextProcess());
EXPECT_EQ(0u, pacer_->QueueSizePackets());
pacer_->ProcessPackets();
// Send some more packet, just show that we can..?
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), 250);
}
EXPECT_EQ(packets_to_send_per_interval, pacer_->QueueSizePackets());
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(0u, pacer_->QueueSizePackets());
}
TEST_P(PacingControllerTest, RepeatedRetransmissionsAllowed) {
// Send one packet, then two retransmissions of that packet.
for (size_t i = 0; i < 3; i++) {
constexpr uint32_t ssrc = 333;
constexpr uint16_t sequence_number = 444;
constexpr size_t bytes = 250;
bool is_retransmission = (i != 0); // Original followed by retransmissions.
SendAndExpectPacket(
is_retransmission ? RtpPacketToSend::Type::kRetransmission
: RtpPacketToSend::Type::kVideo,
ssrc, sequence_number, clock_.TimeInMilliseconds(), bytes);
clock_.AdvanceTimeMilliseconds(5);
}
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > 0) {
AdvanceTimeAndProcess();
}
}
}
TEST_P(PacingControllerTest,
CanQueuePacketsWithSameSequenceNumberOnDifferentSsrcs) {
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number,
clock_.TimeInMilliseconds(), 250);
// Expect packet on second ssrc to be queued and sent as well.
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc + 1, sequence_number,
clock_.TimeInMilliseconds(), 250);
clock_.AdvanceTimeMilliseconds(1000);
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > 0) {
AdvanceTimeAndProcess();
}
}
}
TEST_P(PacingControllerTest, Padding) {
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
const size_t kPacketSize = 250;
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
if (PeriodicProcess()) {
ConsumeInitialBudget();
// 5 milliseconds later should not send padding since we filled the buffers
// initially.
EXPECT_CALL(callback_, SendPadding(kPacketSize)).Times(0);
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
// 5 milliseconds later we have enough budget to send some padding.
EXPECT_CALL(callback_, SendPadding(250)).WillOnce(Return(kPacketSize));
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
const size_t kPacketsToSend = 20;
for (size_t i = 0; i < kPacketsToSend; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc,
sequence_number++, clock_.TimeInMilliseconds(),
kPacketSize);
}
const TimeDelta expected_pace_time =
DataSize::bytes(pacer_->QueueSizePackets() * kPacketSize) /
(kPaceMultiplier * kTargetRate);
EXPECT_CALL(callback_, SendPadding).Times(0);
// Only the media packets should be sent.
Timestamp start_time = clock_.CurrentTime();
while (pacer_->QueueSizePackets() > 0) {
AdvanceTimeAndProcess();
}
const TimeDelta actual_pace_time = clock_.CurrentTime() - start_time;
EXPECT_LE((actual_pace_time - expected_pace_time).Abs(),
PacingController::kMinSleepTime);
// Pacing media happens 2.5x factor, but padding was configured with 1.0x
// factor. We have to wait until the padding debt is gone before we start
// sending padding.
const TimeDelta time_to_padding_debt_free =
(expected_pace_time * kPaceMultiplier) - actual_pace_time;
TimeDelta time_to_next = pacer_->NextSendTime() - clock_.CurrentTime();
EXPECT_EQ(time_to_next, time_to_padding_debt_free);
clock_.AdvanceTime(time_to_next);
// Send 10 padding packets.
const size_t kPaddingPacketsToSend = 10;
DataSize padding_sent = DataSize::Zero();
EXPECT_CALL(callback_, SendPadding)
.Times(kPaddingPacketsToSend)
.WillRepeatedly([&](size_t target_size) {
padding_sent += DataSize::bytes(target_size);
return target_size;
});
EXPECT_CALL(callback_, SendPacket(_, _, _, false, true))
.Times(kPaddingPacketsToSend);
const Timestamp padding_start_time = clock_.CurrentTime();
for (size_t i = 0; i < kPaddingPacketsToSend; ++i) {
AdvanceTimeAndProcess();
}
// Verify rate of sent padding.
TimeDelta padding_duration = pacer_->NextSendTime() - padding_start_time;
DataRate padding_rate = padding_sent / padding_duration;
EXPECT_EQ(padding_rate, kTargetRate);
}
}
TEST_P(PacingControllerTest, NoPaddingBeforeNormalPacket) {
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
EXPECT_CALL(callback_, SendPadding).Times(0);
pacer_->ProcessPackets();
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
clock_.AdvanceTime(TimeUntilNextProcess());
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 56789;
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
capture_time_ms, 250);
EXPECT_CALL(callback_, SendPadding).WillOnce([](size_t padding) {
return padding;
});
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess(); // Media.
AdvanceTimeAndProcess(); // Padding.
}
}
TEST_P(PacingControllerTest, VerifyPaddingUpToBitrate) {
if (!PeriodicProcess()) {
// Already tested in PacingControllerTest.Padding.
return;
}
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 56789;
const int kTimeStep = 5;
const int64_t kBitrateWindow = 100;
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
int64_t start_time = clock_.TimeInMilliseconds();
while (clock_.TimeInMilliseconds() - start_time < kBitrateWindow) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
capture_time_ms, 250);
EXPECT_CALL(callback_, SendPadding(250)).WillOnce(Return(250));
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
pacer_->ProcessPackets();
clock_.AdvanceTimeMilliseconds(kTimeStep);
}
}
TEST_P(PacingControllerTest, VerifyAverageBitrateVaryingMediaPayload) {
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 56789;
const int kTimeStep = 5;
const TimeDelta kAveragingWindowLength = TimeDelta::seconds(10);
PacingControllerPadding callback;
pacer_ = std::make_unique<PacingController>(&clock_, &callback, nullptr,
nullptr, GetParam());
pacer_->SetProbingEnabled(false);
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
Timestamp start_time = clock_.CurrentTime();
size_t media_bytes = 0;
while (clock_.CurrentTime() - start_time < kAveragingWindowLength) {
// Maybe add some new media packets corresponding to expected send rate.
int rand_value = rand(); // NOLINT (rand_r instead of rand)
while (
media_bytes <
(kTargetRate * (clock_.CurrentTime() - start_time)).bytes<size_t>()) {
size_t media_payload = rand_value % 400 + 800; // [400, 1200] bytes.
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
capture_time_ms, media_payload);
media_bytes += media_payload;
}
if (PeriodicProcess()) {
clock_.AdvanceTimeMilliseconds(kTimeStep);
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
EXPECT_NEAR(
kTargetRate.bps(),
(DataSize::bytes(callback.total_bytes_sent()) / kAveragingWindowLength)
.bps(),
(kTargetRate * 0.01 /* 1% error marging */).bps());
}
TEST_P(PacingControllerTest, Priority) {
uint32_t ssrc_low_priority = 12345;
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 56789;
int64_t capture_time_ms_low_priority = 1234567;
ConsumeInitialBudget();
// Expect normal and low priority to be queued and high to pass through.
Send(RtpPacketToSend::Type::kVideo, ssrc_low_priority, sequence_number++,
capture_time_ms_low_priority, 250);
const size_t packets_to_send_per_interval =
kTargetRate.bps() * kPaceMultiplier / (8 * 250 * 200);
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
Send(RtpPacketToSend::Type::kRetransmission, ssrc, sequence_number++,
capture_time_ms, 250);
}
Send(RtpPacketToSend::Type::kAudio, ssrc, sequence_number++, capture_time_ms,
250);
// Expect all high and normal priority to be sent out first.
EXPECT_CALL(callback_, SendPadding).Times(0);
EXPECT_CALL(callback_, SendPacket(ssrc, _, capture_time_ms, _, _))
.Times(packets_to_send_per_interval + 1);
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > 1) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(1u, pacer_->QueueSizePackets());
EXPECT_CALL(callback_, SendPacket(ssrc_low_priority, _,
capture_time_ms_low_priority, _, _))
.Times(1);
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
TEST_P(PacingControllerTest, RetransmissionPriority) {
uint32_t ssrc = 12345;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 45678;
int64_t capture_time_ms_retransmission = 56789;
// Due to the multiplicative factor we can send 5 packets during a send
// interval. (network capacity * multiplier / (8 bits per byte *
// (packet size * #send intervals per second)
const size_t packets_to_send_per_interval =
kTargetRate.bps() * kPaceMultiplier / (8 * 250 * 200);
pacer_->ProcessPackets();
EXPECT_EQ(0u, pacer_->QueueSizePackets());
// Alternate retransmissions and normal packets.
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
capture_time_ms, 250);
Send(RtpPacketToSend::Type::kRetransmission, ssrc, sequence_number++,
capture_time_ms_retransmission, 250);
}
EXPECT_EQ(2 * packets_to_send_per_interval, pacer_->QueueSizePackets());
// Expect all retransmissions to be sent out first despite having a later
// capture time.
EXPECT_CALL(callback_, SendPadding).Times(0);
EXPECT_CALL(callback_, SendPacket(_, _, _, false, _)).Times(0);
EXPECT_CALL(callback_,
SendPacket(ssrc, _, capture_time_ms_retransmission, true, _))
.Times(packets_to_send_per_interval);
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > packets_to_send_per_interval) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(packets_to_send_per_interval, pacer_->QueueSizePackets());
// Expect the remaining (non-retransmission) packets to be sent.
EXPECT_CALL(callback_, SendPadding).Times(0);
EXPECT_CALL(callback_, SendPacket(_, _, _, true, _)).Times(0);
EXPECT_CALL(callback_, SendPacket(ssrc, _, capture_time_ms, false, _))
.Times(packets_to_send_per_interval);
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
while (pacer_->QueueSizePackets() > 0) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(0u, pacer_->QueueSizePackets());
}
TEST_P(PacingControllerTest, HighPrioDoesntAffectBudget) {
const size_t kPacketSize = 250;
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
int64_t capture_time_ms = 56789;
// As high prio packets doesn't affect the budget, we should be able to send
// a high number of them at once.
const size_t kNumAudioPackets = 25;
for (size_t i = 0; i < kNumAudioPackets; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kAudio, ssrc, sequence_number++,
capture_time_ms, kPacketSize);
}
pacer_->ProcessPackets();
// Low prio packets does affect the budget.
// Due to the multiplicative factor we can send 5 packets during a send
// interval. (network capacity * multiplier / (8 bits per byte *
// (packet size * #send intervals per second)
const size_t kPacketsToSendPerInterval =
kTargetRate.bps() * kPaceMultiplier / (8 * kPacketSize * 200);
for (size_t i = 0; i < kPacketsToSendPerInterval; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
// Send all packets and measure pace time.
Timestamp start_time = clock_.CurrentTime();
while (pacer_->QueueSizePackets() > 0) {
if (PeriodicProcess()) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
// Measure pacing time. Expect only low-prio packets to affect this.
TimeDelta pacing_time = clock_.CurrentTime() - start_time;
TimeDelta expected_pacing_time =
DataSize::bytes(kPacketsToSendPerInterval * kPacketSize) /
(kTargetRate * kPaceMultiplier);
EXPECT_NEAR(pacing_time.us<double>(), expected_pacing_time.us<double>(),
PeriodicProcess() ? 5000.0
: PacingController::kMinSleepTime.us<double>());
}
TEST_P(PacingControllerTest, SendsOnlyPaddingWhenCongested) {
uint32_t ssrc = 202020;
uint16_t sequence_number = 1000;
int kPacketSize = 250;
int kCongestionWindow = kPacketSize * 10;
pacer_->UpdateOutstandingData(DataSize::Zero());
pacer_->SetCongestionWindow(DataSize::bytes(kCongestionWindow));
int sent_data = 0;
while (sent_data < kCongestionWindow) {
sent_data += kPacketSize;
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
AdvanceTimeAndProcess();
}
::testing::Mock::VerifyAndClearExpectations(&callback_);
EXPECT_CALL(callback_, SendPacket).Times(0);
EXPECT_CALL(callback_, SendPadding).Times(0);
size_t blocked_packets = 0;
int64_t expected_time_until_padding = 500;
while (expected_time_until_padding > 5) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
blocked_packets++;
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
expected_time_until_padding -= 5;
}
::testing::Mock::VerifyAndClearExpectations(&callback_);
EXPECT_CALL(callback_, SendPadding(1)).WillOnce(Return(1));
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
EXPECT_EQ(blocked_packets, pacer_->QueueSizePackets());
}
TEST_P(PacingControllerTest, DoesNotAllowOveruseAfterCongestion) {
uint32_t ssrc = 202020;
uint16_t seq_num = 1000;
int size = 1000;
auto now_ms = [this] { return clock_.TimeInMilliseconds(); };
EXPECT_CALL(callback_, SendPadding).Times(0);
// The pacing rate is low enough that the budget should not allow two packets
// to be sent in a row.
pacer_->SetPacingRates(DataRate::bps(400 * 8 * 1000 / 5), DataRate::Zero());
// The congestion window is small enough to only let one packet through.
pacer_->SetCongestionWindow(DataSize::bytes(800));
pacer_->UpdateOutstandingData(DataSize::Zero());
// Not yet budget limited or congested, packet is sent.
Send(RtpPacketToSend::Type::kVideo, ssrc, seq_num++, now_ms(), size);
EXPECT_CALL(callback_, SendPacket).Times(1);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
// Packet blocked due to congestion.
Send(RtpPacketToSend::Type::kVideo, ssrc, seq_num++, now_ms(), size);
EXPECT_CALL(callback_, SendPacket).Times(0);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
// Packet blocked due to congestion.
Send(RtpPacketToSend::Type::kVideo, ssrc, seq_num++, now_ms(), size);
EXPECT_CALL(callback_, SendPacket).Times(0);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
// Congestion removed and budget has recovered, packet is sent.
Send(RtpPacketToSend::Type::kVideo, ssrc, seq_num++, now_ms(), size);
EXPECT_CALL(callback_, SendPacket).Times(1);
clock_.AdvanceTimeMilliseconds(5);
pacer_->UpdateOutstandingData(DataSize::Zero());
pacer_->ProcessPackets();
// Should be blocked due to budget limitation as congestion has be removed.
Send(RtpPacketToSend::Type::kVideo, ssrc, seq_num++, now_ms(), size);
EXPECT_CALL(callback_, SendPacket).Times(0);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
}
TEST_P(PacingControllerTest, ResumesSendingWhenCongestionEnds) {
uint32_t ssrc = 202020;
uint16_t sequence_number = 1000;
int64_t kPacketSize = 250;
int64_t kCongestionCount = 10;
int64_t kCongestionWindow = kPacketSize * kCongestionCount;
int64_t kCongestionTimeMs = 1000;
pacer_->UpdateOutstandingData(DataSize::Zero());
pacer_->SetCongestionWindow(DataSize::bytes(kCongestionWindow));
int sent_data = 0;
while (sent_data < kCongestionWindow) {
sent_data += kPacketSize;
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
}
::testing::Mock::VerifyAndClearExpectations(&callback_);
EXPECT_CALL(callback_, SendPacket).Times(0);
int unacked_packets = 0;
for (int duration = 0; duration < kCongestionTimeMs; duration += 5) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
unacked_packets++;
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
}
::testing::Mock::VerifyAndClearExpectations(&callback_);
// First mark half of the congested packets as cleared and make sure that just
// as many are sent
int ack_count = kCongestionCount / 2;
EXPECT_CALL(callback_, SendPacket(ssrc, _, _, false, _)).Times(ack_count);
pacer_->UpdateOutstandingData(
DataSize::bytes(kCongestionWindow - kPacketSize * ack_count));
for (int duration = 0; duration < kCongestionTimeMs; duration += 5) {
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
}
unacked_packets -= ack_count;
::testing::Mock::VerifyAndClearExpectations(&callback_);
// Second make sure all packets are sent if sent packets are continuously
// marked as acked.
EXPECT_CALL(callback_, SendPacket(ssrc, _, _, false, _))
.Times(unacked_packets);
for (int duration = 0; duration < kCongestionTimeMs; duration += 5) {
pacer_->UpdateOutstandingData(DataSize::Zero());
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
}
}
TEST_P(PacingControllerTest, Pause) {
uint32_t ssrc_low_priority = 12345;
uint32_t ssrc = 12346;
uint32_t ssrc_high_priority = 12347;
uint16_t sequence_number = 1234;
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
ConsumeInitialBudget();
pacer_->Pause();
int64_t capture_time_ms = clock_.TimeInMilliseconds();
const size_t packets_to_send_per_interval =
kTargetRate.bps() * kPaceMultiplier / (8 * 250 * 200);
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc_low_priority, sequence_number++,
capture_time_ms, 250);
Send(RtpPacketToSend::Type::kRetransmission, ssrc, sequence_number++,
capture_time_ms, 250);
Send(RtpPacketToSend::Type::kAudio, ssrc_high_priority, sequence_number++,
capture_time_ms, 250);
}
clock_.AdvanceTimeMilliseconds(10000);
int64_t second_capture_time_ms = clock_.TimeInMilliseconds();
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc_low_priority, sequence_number++,
second_capture_time_ms, 250);
Send(RtpPacketToSend::Type::kRetransmission, ssrc, sequence_number++,
second_capture_time_ms, 250);
Send(RtpPacketToSend::Type::kAudio, ssrc_high_priority, sequence_number++,
second_capture_time_ms, 250);
}
// Expect everything to be queued.
EXPECT_EQ(TimeDelta::ms(second_capture_time_ms - capture_time_ms),
pacer_->OldestPacketWaitTime());
// Process triggers keep-alive packet.
EXPECT_CALL(callback_, SendPadding).WillOnce([](size_t padding) {
return padding;
});
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
pacer_->ProcessPackets();
// Verify no packets sent for the rest of the paused process interval.
const TimeDelta kProcessInterval = TimeDelta::ms(5);
TimeDelta expected_time_until_send = PacingController::kPausedProcessInterval;
EXPECT_CALL(callback_, SendPadding).Times(0);
while (expected_time_until_send >= kProcessInterval) {
pacer_->ProcessPackets();
clock_.AdvanceTime(kProcessInterval);
expected_time_until_send -= kProcessInterval;
}
// New keep-alive packet.
::testing::Mock::VerifyAndClearExpectations(&callback_);
EXPECT_CALL(callback_, SendPadding).WillOnce([](size_t padding) {
return padding;
});
EXPECT_CALL(callback_, SendPacket(_, _, _, _, true)).Times(1);
clock_.AdvanceTime(kProcessInterval);
pacer_->ProcessPackets();
::testing::Mock::VerifyAndClearExpectations(&callback_);
// Expect high prio packets to come out first followed by normal
// prio packets and low prio packets (all in capture order).
{
::testing::InSequence sequence;
EXPECT_CALL(callback_,
SendPacket(ssrc_high_priority, _, capture_time_ms, _, _))
.Times(packets_to_send_per_interval);
EXPECT_CALL(callback_,
SendPacket(ssrc_high_priority, _, second_capture_time_ms, _, _))
.Times(packets_to_send_per_interval);
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
EXPECT_CALL(callback_, SendPacket(ssrc, _, capture_time_ms, _, _))
.Times(1);
}
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
EXPECT_CALL(callback_, SendPacket(ssrc, _, second_capture_time_ms, _, _))
.Times(1);
}
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
EXPECT_CALL(callback_,
SendPacket(ssrc_low_priority, _, capture_time_ms, _, _))
.Times(1);
}
for (size_t i = 0; i < packets_to_send_per_interval; ++i) {
EXPECT_CALL(callback_, SendPacket(ssrc_low_priority, _,
second_capture_time_ms, _, _))
.Times(1);
}
}
pacer_->Resume();
if (PeriodicProcess()) {
// The pacer was resumed directly after the previous process call finished.
// It will therefore wait 5 ms until next process.
clock_.AdvanceTime(TimeUntilNextProcess());
for (size_t i = 0; i < 4; i++) {
pacer_->ProcessPackets();
clock_.AdvanceTime(TimeUntilNextProcess());
}
} else {
while (pacer_->QueueSizePackets() > 0) {
AdvanceTimeAndProcess();
}
}
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
}
TEST_P(PacingControllerTest, InactiveFromStart) {
// Recreate the pacer without the inital time forwarding.
pacer_ = std::make_unique<PacingController>(&clock_, &callback_, nullptr,
nullptr, GetParam());
pacer_->SetProbingEnabled(false);
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
if (PeriodicProcess()) {
// In period mode, pause the pacer to check the same idle behavior as
// dynamic.
pacer_->Pause();
}
// No packets sent, there should be no keep-alives sent either.
EXPECT_CALL(callback_, SendPadding).Times(0);
EXPECT_CALL(callback_, SendPacket).Times(0);
pacer_->ProcessPackets();
const Timestamp start_time = clock_.CurrentTime();
// Determine the margin need so we can advance to the last possible moment
// that will not cause a process event.
const TimeDelta time_margin =
(GetParam() == PacingController::ProcessMode::kDynamic
? PacingController::kMinSleepTime
: TimeDelta::Zero()) +
TimeDelta::us(1);
EXPECT_EQ(pacer_->NextSendTime() - start_time,
PacingController::kPausedProcessInterval);
clock_.AdvanceTime(PacingController::kPausedProcessInterval - time_margin);
pacer_->ProcessPackets();
EXPECT_EQ(pacer_->NextSendTime() - start_time,
PacingController::kPausedProcessInterval);
clock_.AdvanceTime(time_margin);
pacer_->ProcessPackets();
EXPECT_EQ(pacer_->NextSendTime() - start_time,
2 * PacingController::kPausedProcessInterval);
}
TEST_P(PacingControllerTest, ExpectedQueueTimeMs) {
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
const size_t kNumPackets = 60;
const size_t kPacketSize = 1200;
const int32_t kMaxBitrate = kPaceMultiplier * 30000;
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
pacer_->SetPacingRates(DataRate::bps(30000 * kPaceMultiplier),
DataRate::Zero());
for (size_t i = 0; i < kNumPackets; ++i) {
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
// Queue in ms = 1000 * (bytes in queue) *8 / (bits per second)
TimeDelta queue_time =
TimeDelta::ms(1000 * kNumPackets * kPacketSize * 8 / kMaxBitrate);
EXPECT_EQ(queue_time, pacer_->ExpectedQueueTime());
const Timestamp time_start = clock_.CurrentTime();
while (pacer_->QueueSizePackets() > 0) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
}
TimeDelta duration = clock_.CurrentTime() - time_start;
EXPECT_EQ(TimeDelta::Zero(), pacer_->ExpectedQueueTime());
// Allow for aliasing, duration should be within one pack of max time limit.
const TimeDelta deviation =
duration - PacingController::kMaxExpectedQueueLength;
EXPECT_LT(deviation.Abs(),
TimeDelta::ms(1000 * kPacketSize * 8 / kMaxBitrate));
}
TEST_P(PacingControllerTest, QueueTimeGrowsOverTime) {
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
pacer_->SetPacingRates(DataRate::bps(30000 * kPaceMultiplier),
DataRate::Zero());
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number,
clock_.TimeInMilliseconds(), 1200);
clock_.AdvanceTimeMilliseconds(500);
EXPECT_EQ(TimeDelta::ms(500), pacer_->OldestPacketWaitTime());
pacer_->ProcessPackets();
EXPECT_EQ(TimeDelta::Zero(), pacer_->OldestPacketWaitTime());
}
TEST_P(PacingControllerTest, ProbingWithInsertedPackets) {
const size_t kPacketSize = 1200;
const int kInitialBitrateBps = 300000;
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
PacingControllerProbing packet_sender;
pacer_ = std::make_unique<PacingController>(&clock_, &packet_sender, nullptr,
nullptr, GetParam());
pacer_->CreateProbeCluster(kFirstClusterRate,
/*cluster_id=*/0);
pacer_->CreateProbeCluster(kSecondClusterRate,
/*cluster_id=*/1);
pacer_->SetPacingRates(DataRate::bps(kInitialBitrateBps * kPaceMultiplier),
DataRate::Zero());
for (int i = 0; i < 10; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
int64_t start = clock_.TimeInMilliseconds();
while (packet_sender.packets_sent() < 5) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
}
int packets_sent = packet_sender.packets_sent();
// Validate first cluster bitrate. Note that we have to account for number
// of intervals and hence (packets_sent - 1) on the first cluster.
EXPECT_NEAR((packets_sent - 1) * kPacketSize * 8000 /
(clock_.TimeInMilliseconds() - start),
kFirstClusterRate.bps(), kProbingErrorMargin.bps());
EXPECT_EQ(0, packet_sender.padding_sent());
clock_.AdvanceTime(TimeUntilNextProcess());
start = clock_.TimeInMilliseconds();
while (packet_sender.packets_sent() < 10) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
}
packets_sent = packet_sender.packets_sent() - packets_sent;
// Validate second cluster bitrate.
EXPECT_NEAR((packets_sent - 1) * kPacketSize * 8000 /
(clock_.TimeInMilliseconds() - start),
kSecondClusterRate.bps(), kProbingErrorMargin.bps());
}
TEST_P(PacingControllerTest, SkipsProbesWhenProcessIntervalTooLarge) {
const size_t kPacketSize = 1200;
const int kInitialBitrateBps = 300000;
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
PacingControllerProbing packet_sender;
pacer_ = std::make_unique<PacingController>(&clock_, &packet_sender, nullptr,
nullptr, GetParam());
pacer_->SetPacingRates(DataRate::bps(kInitialBitrateBps * kPaceMultiplier),
DataRate::Zero());
for (int i = 0; i < 10; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
while (pacer_->QueueSizePackets() > 0) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
}
// Probe at a very high rate.
pacer_->CreateProbeCluster(DataRate::kbps(10000), // 10 Mbps.
/*cluster_id=*/3);
// We need one packet to start the probe.
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
const int packets_sent_before_probe = packet_sender.packets_sent();
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
EXPECT_EQ(packet_sender.packets_sent(), packets_sent_before_probe + 1);
// Figure out how long between probe packets.
Timestamp start_time = clock_.CurrentTime();
clock_.AdvanceTime(TimeUntilNextProcess());
TimeDelta time_between_probes = clock_.CurrentTime() - start_time;
// Advance that distance again + 1ms.
clock_.AdvanceTime(time_between_probes);
// Send second probe packet.
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
pacer_->ProcessPackets();
EXPECT_EQ(packet_sender.packets_sent(), packets_sent_before_probe + 2);
// We're exactly where we should be for the next probe.
const Timestamp probe_time = clock_.CurrentTime();
EXPECT_EQ(pacer_->NextSendTime(), clock_.CurrentTime());
FieldTrialBasedConfig field_trial_config;
BitrateProberConfig probing_config(&field_trial_config);
EXPECT_GT(probing_config.max_probe_delay.Get(), TimeDelta::Zero());
// Advance to within max probe delay, should still return same target.
clock_.AdvanceTime(probing_config.max_probe_delay.Get());
EXPECT_EQ(pacer_->NextSendTime(), probe_time);
// Too high probe delay, drop it!
clock_.AdvanceTime(TimeDelta::us(1));
EXPECT_GT(pacer_->NextSendTime(), probe_time);
}
TEST_P(PacingControllerTest, ProbingWithPaddingSupport) {
const size_t kPacketSize = 1200;
const int kInitialBitrateBps = 300000;
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
PacingControllerProbing packet_sender;
pacer_ = std::make_unique<PacingController>(&clock_, &packet_sender, nullptr,
nullptr, GetParam());
pacer_->CreateProbeCluster(kFirstClusterRate,
/*cluster_id=*/0);
pacer_->SetPacingRates(DataRate::bps(kInitialBitrateBps * kPaceMultiplier),
DataRate::Zero());
for (int i = 0; i < 3; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
int64_t start = clock_.TimeInMilliseconds();
int process_count = 0;
while (process_count < 5) {
clock_.AdvanceTime(TimeUntilNextProcess());
pacer_->ProcessPackets();
++process_count;
}
int packets_sent = packet_sender.packets_sent();
int padding_sent = packet_sender.padding_sent();
EXPECT_GT(packets_sent, 0);
EXPECT_GT(padding_sent, 0);
// Note that the number of intervals here for kPacketSize is
// packets_sent due to padding in the same cluster.
EXPECT_NEAR((packets_sent * kPacketSize * 8000 + padding_sent) /
(clock_.TimeInMilliseconds() - start),
kFirstClusterRate.bps(), kProbingErrorMargin.bps());
}
TEST_P(PacingControllerTest, PaddingOveruse) {
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
const size_t kPacketSize = 1200;
// Initially no padding rate.
pacer_->ProcessPackets();
pacer_->SetPacingRates(DataRate::bps(60000 * kPaceMultiplier),
DataRate::Zero());
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
pacer_->ProcessPackets();
// Add 30kbit padding. When increasing budget, media budget will increase from
// negative (overuse) while padding budget will increase from 0.
clock_.AdvanceTimeMilliseconds(5);
pacer_->SetPacingRates(DataRate::bps(60000 * kPaceMultiplier),
DataRate::bps(30000));
SendAndExpectPacket(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
EXPECT_LT(TimeDelta::ms(5), pacer_->ExpectedQueueTime());
// Don't send padding if queue is non-empty, even if padding budget > 0.
EXPECT_CALL(callback_, SendPadding).Times(0);
if (PeriodicProcess()) {
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
TEST_P(PacingControllerTest, ProbeClusterId) {
MockPacketSender callback;
pacer_ = std::make_unique<PacingController>(&clock_, &callback, nullptr,
nullptr, GetParam());
Init();
uint32_t ssrc = 12346;
uint16_t sequence_number = 1234;
const size_t kPacketSize = 1200;
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, kTargetRate);
pacer_->SetProbingEnabled(true);
for (int i = 0; i < 10; ++i) {
Send(RtpPacketToSend::Type::kVideo, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), kPacketSize);
}
// First probing cluster.
EXPECT_CALL(callback,
SendRtpPacket(_, Field(&PacedPacketInfo::probe_cluster_id, 0)))
.Times(5);
for (int i = 0; i < 5; ++i) {
AdvanceTimeAndProcess();
}
// Second probing cluster.
EXPECT_CALL(callback,
SendRtpPacket(_, Field(&PacedPacketInfo::probe_cluster_id, 1)))
.Times(5);
for (int i = 0; i < 5; ++i) {
AdvanceTimeAndProcess();
}
// Needed for the Field comparer below.
const int kNotAProbe = PacedPacketInfo::kNotAProbe;
// No more probing packets.
EXPECT_CALL(callback, GeneratePadding).WillOnce([&](DataSize padding_size) {
std::vector<std::unique_ptr<RtpPacketToSend>> padding_packets;
padding_packets.emplace_back(
BuildPacket(RtpPacketToSend::Type::kPadding, ssrc, sequence_number++,
clock_.TimeInMilliseconds(), padding_size.bytes()));
return padding_packets;
});
bool non_probe_packet_seen = false;
EXPECT_CALL(callback, SendRtpPacket)
.WillOnce([&](std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& cluster_info) {
EXPECT_EQ(cluster_info.probe_cluster_id, kNotAProbe);
non_probe_packet_seen = true;
});
while (!non_probe_packet_seen) {
AdvanceTimeAndProcess();
}
}
TEST_P(PacingControllerTest, OwnedPacketPrioritizedOnType) {
MockPacketSender callback;
pacer_ = std::make_unique<PacingController>(&clock_, &callback, nullptr,
nullptr, GetParam());
Init();
// Insert a packet of each type, from low to high priority. Since priority
// is weighted higher than insert order, these should come out of the pacer
// in backwards order with the exception of FEC and Video.
for (RtpPacketToSend::Type type :
{RtpPacketToSend::Type::kPadding,
RtpPacketToSend::Type::kForwardErrorCorrection,
RtpPacketToSend::Type::kVideo, RtpPacketToSend::Type::kRetransmission,
RtpPacketToSend::Type::kAudio}) {
pacer_->EnqueuePacket(BuildRtpPacket(type));
}
::testing::InSequence seq;
EXPECT_CALL(
callback,
SendRtpPacket(Pointee(Property(&RtpPacketToSend::Ssrc, kAudioSsrc)), _));
EXPECT_CALL(callback,
SendRtpPacket(
Pointee(Property(&RtpPacketToSend::Ssrc, kVideoRtxSsrc)), _));
// FEC and video actually have the same priority, so will come out in
// insertion order.
EXPECT_CALL(callback,
SendRtpPacket(
Pointee(Property(&RtpPacketToSend::Ssrc, kFlexFecSsrc)), _));
EXPECT_CALL(
callback,
SendRtpPacket(Pointee(Property(&RtpPacketToSend::Ssrc, kVideoSsrc)), _));
EXPECT_CALL(callback,
SendRtpPacket(
Pointee(Property(&RtpPacketToSend::Ssrc, kVideoRtxSsrc)), _));
while (pacer_->QueueSizePackets() > 0) {
if (PeriodicProcess()) {
clock_.AdvanceTimeMilliseconds(5);
pacer_->ProcessPackets();
} else {
AdvanceTimeAndProcess();
}
}
}
TEST_P(PacingControllerTest, SmallFirstProbePacket) {
ScopedFieldTrials trial("WebRTC-Pacer-SmallFirstProbePacket/Enabled/");
MockPacketSender callback;
pacer_ = std::make_unique<PacingController>(&clock_, &callback, nullptr,
nullptr, GetParam());
pacer_->CreateProbeCluster(kFirstClusterRate, /*cluster_id=*/0);
pacer_->SetPacingRates(kTargetRate * kPaceMultiplier, DataRate::Zero());
// Add high prio media.
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kAudio));
// Expect small padding packet to be requested.
EXPECT_CALL(callback, GeneratePadding(DataSize::bytes(1)))
.WillOnce([&](DataSize padding_size) {
std::vector<std::unique_ptr<RtpPacketToSend>> padding_packets;
padding_packets.emplace_back(
BuildPacket(RtpPacketToSend::Type::kPadding, kAudioSsrc, 1,
clock_.TimeInMilliseconds(), 1));
return padding_packets;
});
size_t packets_sent = 0;
bool media_seen = false;
EXPECT_CALL(callback, SendRtpPacket)
.Times(::testing::AnyNumber())
.WillRepeatedly([&](std::unique_ptr<RtpPacketToSend> packet,
const PacedPacketInfo& cluster_info) {
if (packets_sent == 0) {
EXPECT_EQ(packet->packet_type(), RtpPacketToSend::Type::kPadding);
} else {
if (packet->packet_type() == RtpPacketToSend::Type::kAudio) {
media_seen = true;
}
}
packets_sent++;
});
while (!media_seen) {
pacer_->ProcessPackets();
clock_.AdvanceTimeMilliseconds(5);
}
}
TEST_P(PacingControllerTest, TaskEarly) {
if (PeriodicProcess()) {
// This test applies only when NOT using interval budget.
return;
}
// Set a low send rate to more easily test timing issues.
DataRate kSendRate = DataRate::kbps(30);
pacer_->SetPacingRates(kSendRate, DataRate::Zero());
// Add two packets.
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
// Process packets, only first should be sent.
EXPECT_CALL(callback_, SendPacket).Times(1);
pacer_->ProcessPackets();
Timestamp next_send_time = pacer_->NextSendTime();
// Packets won't be sent if we try process more than one sleep time early.
ASSERT_GT(next_send_time - clock_.CurrentTime(),
PacingController::kMinSleepTime);
clock_.AdvanceTime(next_send_time - clock_.CurrentTime() -
(PacingController::kMinSleepTime + TimeDelta::ms(1)));
EXPECT_CALL(callback_, SendPacket).Times(0);
pacer_->ProcessPackets();
// Assume timing is accurate within +-100us due to rounding.
const TimeDelta kErrorMargin = TimeDelta::us(100);
// Check that next scheduled send time is still the same (within margin).
EXPECT_LT((pacer_->NextSendTime() - next_send_time).Abs(), kErrorMargin);
// Advance to within error margin for execution.
clock_.AdvanceTime(TimeDelta::ms(1) + kErrorMargin);
EXPECT_CALL(callback_, SendPacket).Times(1);
pacer_->ProcessPackets();
}
TEST_P(PacingControllerTest, TaskLate) {
if (PeriodicProcess()) {
// This test applies only when NOT using interval budget.
return;
}
// Set a low send rate to more easily test timing issues.
DataRate kSendRate = DataRate::kbps(30);
pacer_->SetPacingRates(kSendRate, DataRate::Zero());
// Add four packets of equal size and priority.
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
pacer_->EnqueuePacket(BuildRtpPacket(RtpPacketToSend::Type::kVideo));
// Process packets, only first should be sent.
EXPECT_CALL(callback_, SendPacket).Times(1);
pacer_->ProcessPackets();
Timestamp next_send_time = pacer_->NextSendTime();
const TimeDelta time_between_packets = next_send_time - clock_.CurrentTime();
// Simulate a late process call, executed just before we allow sending the
// fourth packet.
clock_.AdvanceTime((time_between_packets * 3) -
(PacingController::kMinSleepTime + TimeDelta::ms(1)));
EXPECT_CALL(callback_, SendPacket).Times(2);
pacer_->ProcessPackets();
// Check that next scheduled send time is within sleep-time + 1ms.
next_send_time = pacer_->NextSendTime();
EXPECT_LE(next_send_time - clock_.CurrentTime(),
PacingController::kMinSleepTime + TimeDelta::ms(1));
// Advance to within error margin for execution.
clock_.AdvanceTime(TimeDelta::ms(1));
EXPECT_CALL(callback_, SendPacket).Times(1);
pacer_->ProcessPackets();
}
INSTANTIATE_TEST_SUITE_P(
WithAndWithoutIntervalBudget,
PacingControllerTest,
::testing::Values(PacingController::ProcessMode::kPeriodic,
PacingController::ProcessMode::kDynamic));
} // namespace test
} // namespace webrtc
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