blob: d39417bf4589b44774771b6e36b1368b3a196d3e [file] [log] [blame]
* 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 <stddef.h>
#include <stdint.h>
#include <functional>
#include <memory>
#include <queue>
#include <vector>
#include "absl/types/optional.h"
#include "api/sequence_checker.h"
#include "api/task_queue/task_queue_factory.h"
#include "api/units/data_size.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "modules/include/module.h"
#include "modules/pacing/pacing_controller.h"
#include "modules/pacing/rtp_packet_pacer.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/synchronization/mutex.h"
#include "rtc_base/task_queue.h"
#include "rtc_base/thread_annotations.h"
namespace webrtc {
class Clock;
class RtcEventLog;
class TaskQueuePacedSender : public RtpPacketPacer, public RtpPacketSender {
// The `hold_back_window` parameter sets a lower bound on time to sleep if
// there is currently a pacer queue and packets can't immediately be
// processed. Increasing this reduces thread wakeups at the expense of higher
// latency.
// TODO( Remove default value for hold_back_window.
Clock* clock,
PacingController::PacketSender* packet_sender,
RtcEventLog* event_log,
const WebRtcKeyValueConfig* field_trials,
TaskQueueFactory* task_queue_factory,
TimeDelta hold_back_window = PacingController::kMinSleepTime);
~TaskQueuePacedSender() override;
// Ensure that necessary delayed tasks are scheduled.
void EnsureStarted();
// Methods implementing RtpPacketSender.
// Adds the packet to the queue and calls
// PacingController::PacketSender::SendPacket() when it's time to send.
void EnqueuePackets(
std::vector<std::unique_ptr<RtpPacketToSend>> packets) override;
// Methods implementing RtpPacketPacer:
void CreateProbeCluster(DataRate bitrate, int cluster_id) override;
// Temporarily pause all sending.
void Pause() override;
// Resume sending packets.
void Resume() override;
void SetCongestionWindow(DataSize congestion_window_size) override;
void UpdateOutstandingData(DataSize outstanding_data) override;
// Sets the pacing rates. Must be called once before packets can be sent.
void SetPacingRates(DataRate pacing_rate, DataRate padding_rate) override;
// Currently audio traffic is not accounted for by pacer and passed through.
// With the introduction of audio BWE, audio traffic will be accounted for
// in the pacer budget calculation. The audio traffic will still be injected
// at high priority.
void SetAccountForAudioPackets(bool account_for_audio) override;
void SetIncludeOverhead() override;
void SetTransportOverhead(DataSize overhead_per_packet) override;
// Returns the time since the oldest queued packet was enqueued.
TimeDelta OldestPacketWaitTime() const override;
// Returns total size of all packets in the pacer queue.
DataSize QueueSizeData() const override;
// Returns the time when the first packet was sent;
absl::optional<Timestamp> FirstSentPacketTime() const override;
// Returns the number of milliseconds it will take to send the current
// packets in the queue, given the current size and bitrate, ignoring prio.
TimeDelta ExpectedQueueTime() const override;
// Set the max desired queuing delay, pacer will override the pacing rate
// specified by SetPacingRates() if needed to achieve this goal.
void SetQueueTimeLimit(TimeDelta limit) override;
// Exposed as protected for test.
struct Stats {
: oldest_packet_wait_time(TimeDelta::Zero()),
expected_queue_time(TimeDelta::Zero()) {}
TimeDelta oldest_packet_wait_time;
DataSize queue_size;
TimeDelta expected_queue_time;
absl::optional<Timestamp> first_sent_packet_time;
virtual void OnStatsUpdated(const Stats& stats);
// Check if it is time to send packets, or schedule a delayed task if not.
// Use Timestamp::MinusInfinity() to indicate that this call has _not_
// been scheduled by the pacing controller. If this is the case, check if
// can execute immediately otherwise schedule a delay task that calls this
// method again with desired (finite) scheduled process time.
void MaybeProcessPackets(Timestamp scheduled_process_time);
void MaybeUpdateStats(bool is_scheduled_call) RTC_RUN_ON(task_queue_);
Stats GetStats() const;
Clock* const clock_;
const TimeDelta hold_back_window_;
PacingController pacing_controller_ RTC_GUARDED_BY(task_queue_);
// We want only one (valid) delayed process task in flight at a time.
// If the value of `next_process_time_` is finite, it is an id for a
// delayed task that will call MaybeProcessPackets() with that time
// as parameter.
// Timestamp::MinusInfinity() indicates no valid pending task.
Timestamp next_process_time_ RTC_GUARDED_BY(task_queue_);
// Since we don't want to support synchronous calls that wait for a
// task execution, we poll the stats at some interval and update
// `current_stats_`, which can in turn be polled at any time.
// True iff there is delayed task in flight that that will call
// UdpateStats().
bool stats_update_scheduled_ RTC_GUARDED_BY(task_queue_);
// Last time stats were updated.
Timestamp last_stats_time_ RTC_GUARDED_BY(task_queue_);
// Indicates if this task queue is started. If not, don't allow
// posting delayed tasks yet.
bool is_started_ RTC_GUARDED_BY(task_queue_) = false;
// Indicates if this task queue is shutting down. If so, don't allow
// posting any more delayed tasks as that can cause the task queue to
// never drain.
bool is_shutdown_ RTC_GUARDED_BY(task_queue_);
mutable Mutex stats_mutex_;
Stats current_stats_ RTC_GUARDED_BY(stats_mutex_);
rtc::TaskQueue task_queue_;
} // namespace webrtc