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/*
* Copyright 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 "call/simulated_network.h"
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include "absl/algorithm/container.h"
#include "api/units/data_rate.h"
#include "test/gtest.h"
namespace webrtc {
namespace {
constexpr int kNotReceived = PacketDeliveryInfo::kNotReceived;
}
TEST(SimulatedNetworkTest, CodelDoesNothingAtCapacity) {
const TimeDelta kRuntime = TimeDelta::Seconds(30);
DataRate link_capacity = DataRate::KilobitsPerSec(1000);
const DataSize packet_size = DataSize::Bytes(1000);
SimulatedNetwork::Config config;
config.codel_active_queue_management = true;
config.queue_delay_ms = 10;
config.link_capacity_kbps = link_capacity.kbps();
SimulatedNetwork network(config);
// Need to round up here as otherwise we actually will choke.
const TimeDelta packet_inverval =
packet_size / link_capacity + TimeDelta::Millis(1);
// Send at capacity and see we get no loss.
Timestamp start_time = Timestamp::Millis(0);
Timestamp current_time = start_time;
Timestamp next_packet_time = start_time;
uint64_t next_id = 0;
std::set<uint64_t> pending;
while (current_time - start_time < kRuntime) {
if (current_time >= next_packet_time) {
bool success = network.EnqueuePacket(PacketInFlightInfo{
packet_size.bytes<size_t>(), current_time.us(), next_id});
EXPECT_TRUE(success);
pending.insert(next_id);
++next_id;
next_packet_time += packet_inverval;
}
Timestamp next_delivery = Timestamp::PlusInfinity();
if (network.NextDeliveryTimeUs())
next_delivery = Timestamp::Micros(*network.NextDeliveryTimeUs());
current_time = std::min(next_packet_time, next_delivery);
if (current_time >= next_delivery) {
for (PacketDeliveryInfo packet :
network.DequeueDeliverablePackets(current_time.us())) {
EXPECT_NE(packet.receive_time_us, kNotReceived);
pending.erase(packet.packet_id);
}
}
}
while (network.NextDeliveryTimeUs()) {
for (PacketDeliveryInfo packet :
network.DequeueDeliverablePackets(*network.NextDeliveryTimeUs())) {
EXPECT_NE(packet.receive_time_us, kNotReceived);
pending.erase(packet.packet_id);
}
}
EXPECT_EQ(pending.size(), 0u);
}
TEST(SimulatedNetworkTest, CodelLimitsDelayAndDropsPacketsOnOverload) {
const TimeDelta kRuntime = TimeDelta::Seconds(30);
const TimeDelta kCheckInterval = TimeDelta::Millis(2000);
DataRate link_capacity = DataRate::KilobitsPerSec(1000);
const DataSize rough_packet_size = DataSize::Bytes(1500);
const double overload_rate = 1.5;
SimulatedNetwork::Config config;
config.codel_active_queue_management = true;
config.queue_delay_ms = 10;
config.link_capacity_kbps = link_capacity.kbps();
SimulatedNetwork network(config);
const TimeDelta packet_inverval = rough_packet_size / link_capacity;
const DataSize packet_size = overload_rate * link_capacity * packet_inverval;
// Send above capacity and see delays are still controlled at the cost of
// packet loss.
Timestamp start_time = Timestamp::Millis(0);
Timestamp current_time = start_time;
Timestamp next_packet_time = start_time;
Timestamp last_check = start_time;
uint64_t next_id = 1;
std::map<uint64_t, int64_t> send_times_us;
int lost = 0;
std::vector<int64_t> delays_us;
while (current_time - start_time < kRuntime) {
if (current_time >= next_packet_time) {
bool success = network.EnqueuePacket(PacketInFlightInfo{
packet_size.bytes<size_t>(), current_time.us(), next_id});
send_times_us.insert({next_id, current_time.us()});
++next_id;
EXPECT_TRUE(success);
next_packet_time += packet_inverval;
}
Timestamp next_delivery = Timestamp::PlusInfinity();
if (network.NextDeliveryTimeUs())
next_delivery = Timestamp::Micros(*network.NextDeliveryTimeUs());
current_time = std::min(next_packet_time, next_delivery);
if (current_time >= next_delivery) {
for (PacketDeliveryInfo packet :
network.DequeueDeliverablePackets(current_time.us())) {
if (packet.receive_time_us == kNotReceived) {
++lost;
} else {
delays_us.push_back(packet.receive_time_us -
send_times_us[packet.packet_id]);
}
send_times_us.erase(packet.packet_id);
}
}
if (current_time > last_check + kCheckInterval) {
last_check = current_time;
TimeDelta average_delay =
TimeDelta::Micros(absl::c_accumulate(delays_us, 0)) /
delays_us.size();
double loss_ratio = static_cast<double>(lost) / (lost + delays_us.size());
EXPECT_LT(average_delay.ms(), 200)
<< "Time " << (current_time - start_time).ms() << "\n";
EXPECT_GT(loss_ratio, 0.5 * (overload_rate - 1));
}
}
while (network.NextDeliveryTimeUs()) {
for (PacketDeliveryInfo packet :
network.DequeueDeliverablePackets(*network.NextDeliveryTimeUs())) {
send_times_us.erase(packet.packet_id);
}
}
EXPECT_EQ(send_times_us.size(), 0u);
}
} // namespace webrtc
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