af476c737f
There's no longer any need to make the two arguments have the same signedness, so we can drop the "u" suffix on literal integer arguments. NOPRESUBMIT=true BUG=webrtc:6645 Review-Url: https://codereview.webrtc.org/2535593002 Cr-Commit-Position: refs/heads/master@{#15280}
511 lines
17 KiB
C++
511 lines
17 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/pacing/paced_sender.h"
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#include <algorithm>
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#include <map>
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#include <queue>
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#include <set>
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#include <vector>
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#include "webrtc/base/checks.h"
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#include "webrtc/base/logging.h"
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#include "webrtc/modules/include/module_common_types.h"
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#include "webrtc/modules/pacing/alr_detector.h"
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#include "webrtc/modules/pacing/bitrate_prober.h"
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#include "webrtc/system_wrappers/include/clock.h"
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#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
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#include "webrtc/system_wrappers/include/field_trial.h"
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namespace {
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// Time limit in milliseconds between packet bursts.
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const int64_t kMinPacketLimitMs = 5;
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// Upper cap on process interval, in case process has not been called in a long
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// time.
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const int64_t kMaxIntervalTimeMs = 30;
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} // namespace
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// TODO(sprang): Move at least PacketQueue and MediaBudget out to separate
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// files, so that we can more easily test them.
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namespace webrtc {
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namespace paced_sender {
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struct Packet {
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Packet(RtpPacketSender::Priority priority,
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uint32_t ssrc,
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uint16_t seq_number,
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int64_t capture_time_ms,
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int64_t enqueue_time_ms,
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size_t length_in_bytes,
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bool retransmission,
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uint64_t enqueue_order)
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: priority(priority),
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ssrc(ssrc),
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sequence_number(seq_number),
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capture_time_ms(capture_time_ms),
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enqueue_time_ms(enqueue_time_ms),
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bytes(length_in_bytes),
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retransmission(retransmission),
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enqueue_order(enqueue_order) {}
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RtpPacketSender::Priority priority;
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uint32_t ssrc;
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uint16_t sequence_number;
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int64_t capture_time_ms;
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int64_t enqueue_time_ms;
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size_t bytes;
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bool retransmission;
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uint64_t enqueue_order;
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std::list<Packet>::iterator this_it;
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};
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// Used by priority queue to sort packets.
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struct Comparator {
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bool operator()(const Packet* first, const Packet* second) {
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// Highest prio = 0.
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if (first->priority != second->priority)
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return first->priority > second->priority;
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// Retransmissions go first.
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if (second->retransmission != first->retransmission)
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return second->retransmission;
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// Older frames have higher prio.
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if (first->capture_time_ms != second->capture_time_ms)
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return first->capture_time_ms > second->capture_time_ms;
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return first->enqueue_order > second->enqueue_order;
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}
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};
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// Class encapsulating a priority queue with some extensions.
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class PacketQueue {
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public:
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explicit PacketQueue(Clock* clock)
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: bytes_(0),
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clock_(clock),
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queue_time_sum_(0),
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time_last_updated_(clock_->TimeInMilliseconds()) {}
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virtual ~PacketQueue() {}
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void Push(const Packet& packet) {
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if (!AddToDupeSet(packet))
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return;
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UpdateQueueTime(packet.enqueue_time_ms);
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// Store packet in list, use pointers in priority queue for cheaper moves.
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// Packets have a handle to its own iterator in the list, for easy removal
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// when popping from queue.
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packet_list_.push_front(packet);
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std::list<Packet>::iterator it = packet_list_.begin();
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it->this_it = it; // Handle for direct removal from list.
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prio_queue_.push(&(*it)); // Pointer into list.
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bytes_ += packet.bytes;
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}
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const Packet& BeginPop() {
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const Packet& packet = *prio_queue_.top();
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prio_queue_.pop();
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return packet;
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}
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void CancelPop(const Packet& packet) { prio_queue_.push(&(*packet.this_it)); }
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void FinalizePop(const Packet& packet) {
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RemoveFromDupeSet(packet);
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bytes_ -= packet.bytes;
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queue_time_sum_ -= (time_last_updated_ - packet.enqueue_time_ms);
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packet_list_.erase(packet.this_it);
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RTC_DCHECK_EQ(packet_list_.size(), prio_queue_.size());
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if (packet_list_.empty())
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RTC_DCHECK_EQ(0, queue_time_sum_);
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}
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bool Empty() const { return prio_queue_.empty(); }
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size_t SizeInPackets() const { return prio_queue_.size(); }
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uint64_t SizeInBytes() const { return bytes_; }
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int64_t OldestEnqueueTimeMs() const {
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auto it = packet_list_.rbegin();
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if (it == packet_list_.rend())
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return 0;
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return it->enqueue_time_ms;
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}
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void UpdateQueueTime(int64_t timestamp_ms) {
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RTC_DCHECK_GE(timestamp_ms, time_last_updated_);
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int64_t delta = timestamp_ms - time_last_updated_;
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// Use packet packet_list_.size() not prio_queue_.size() here, as there
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// might be an outstanding element popped from prio_queue_ currently in the
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// SendPacket() call, while packet_list_ will always be correct.
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queue_time_sum_ += delta * packet_list_.size();
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time_last_updated_ = timestamp_ms;
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}
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int64_t AverageQueueTimeMs() const {
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if (prio_queue_.empty())
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return 0;
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return queue_time_sum_ / packet_list_.size();
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}
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private:
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// Try to add a packet to the set of ssrc/seqno identifiers currently in the
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// queue. Return true if inserted, false if this is a duplicate.
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bool AddToDupeSet(const Packet& packet) {
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SsrcSeqNoMap::iterator it = dupe_map_.find(packet.ssrc);
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if (it == dupe_map_.end()) {
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// First for this ssrc, just insert.
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dupe_map_[packet.ssrc].insert(packet.sequence_number);
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return true;
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}
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// Insert returns a pair, where second is a bool set to true if new element.
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return it->second.insert(packet.sequence_number).second;
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}
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void RemoveFromDupeSet(const Packet& packet) {
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SsrcSeqNoMap::iterator it = dupe_map_.find(packet.ssrc);
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RTC_DCHECK(it != dupe_map_.end());
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it->second.erase(packet.sequence_number);
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if (it->second.empty()) {
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dupe_map_.erase(it);
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}
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}
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// List of packets, in the order the were enqueued. Since dequeueing may
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// occur out of order, use list instead of vector.
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std::list<Packet> packet_list_;
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// Priority queue of the packets, sorted according to Comparator.
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// Use pointers into list, to avoid moving whole struct within heap.
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std::priority_queue<Packet*, std::vector<Packet*>, Comparator> prio_queue_;
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// Total number of bytes in the queue.
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uint64_t bytes_;
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// Map<ssrc, set<seq_no> >, for checking duplicates.
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typedef std::map<uint32_t, std::set<uint16_t> > SsrcSeqNoMap;
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SsrcSeqNoMap dupe_map_;
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Clock* const clock_;
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int64_t queue_time_sum_;
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int64_t time_last_updated_;
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};
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class IntervalBudget {
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public:
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explicit IntervalBudget(int initial_target_rate_kbps)
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: target_rate_kbps_(initial_target_rate_kbps),
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bytes_remaining_(0) {}
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void set_target_rate_kbps(int target_rate_kbps) {
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target_rate_kbps_ = target_rate_kbps;
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bytes_remaining_ =
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std::max(-kWindowMs * target_rate_kbps_ / 8, bytes_remaining_);
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}
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void IncreaseBudget(int64_t delta_time_ms) {
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int64_t bytes = target_rate_kbps_ * delta_time_ms / 8;
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if (bytes_remaining_ < 0) {
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// We overused last interval, compensate this interval.
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bytes_remaining_ = bytes_remaining_ + bytes;
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} else {
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// If we underused last interval we can't use it this interval.
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bytes_remaining_ = bytes;
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}
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}
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void UseBudget(size_t bytes) {
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bytes_remaining_ = std::max(bytes_remaining_ - static_cast<int>(bytes),
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-kWindowMs * target_rate_kbps_ / 8);
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}
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size_t bytes_remaining() const {
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return static_cast<size_t>(std::max(0, bytes_remaining_));
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}
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int target_rate_kbps() const { return target_rate_kbps_; }
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private:
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static const int kWindowMs = 500;
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int target_rate_kbps_;
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int bytes_remaining_;
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};
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} // namespace paced_sender
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const int64_t PacedSender::kMaxQueueLengthMs = 2000;
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const float PacedSender::kDefaultPaceMultiplier = 2.5f;
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PacedSender::PacedSender(Clock* clock, PacketSender* packet_sender)
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: clock_(clock),
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packet_sender_(packet_sender),
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alr_detector_(new AlrDetector()),
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critsect_(CriticalSectionWrapper::CreateCriticalSection()),
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paused_(false),
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media_budget_(new paced_sender::IntervalBudget(0)),
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padding_budget_(new paced_sender::IntervalBudget(0)),
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prober_(new BitrateProber()),
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estimated_bitrate_bps_(0),
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min_send_bitrate_kbps_(0u),
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max_padding_bitrate_kbps_(0u),
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pacing_bitrate_kbps_(0),
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time_last_update_us_(clock->TimeInMicroseconds()),
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packets_(new paced_sender::PacketQueue(clock)),
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packet_counter_(0) {
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UpdateBudgetWithElapsedTime(kMinPacketLimitMs);
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}
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PacedSender::~PacedSender() {}
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void PacedSender::CreateProbeCluster(int bitrate_bps, int num_packets) {
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CriticalSectionScoped cs(critsect_.get());
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prober_->CreateProbeCluster(bitrate_bps, num_packets);
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}
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void PacedSender::Pause() {
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LOG(LS_INFO) << "PacedSender paused.";
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CriticalSectionScoped cs(critsect_.get());
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paused_ = true;
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}
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void PacedSender::Resume() {
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LOG(LS_INFO) << "PacedSender resumed.";
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CriticalSectionScoped cs(critsect_.get());
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paused_ = false;
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}
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void PacedSender::SetProbingEnabled(bool enabled) {
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RTC_CHECK_EQ(0, packet_counter_);
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CriticalSectionScoped cs(critsect_.get());
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prober_->SetEnabled(enabled);
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}
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void PacedSender::SetEstimatedBitrate(uint32_t bitrate_bps) {
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if (bitrate_bps == 0)
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LOG(LS_ERROR) << "PacedSender is not designed to handle 0 bitrate.";
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CriticalSectionScoped cs(critsect_.get());
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estimated_bitrate_bps_ = bitrate_bps;
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padding_budget_->set_target_rate_kbps(
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std::min(estimated_bitrate_bps_ / 1000, max_padding_bitrate_kbps_));
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pacing_bitrate_kbps_ =
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std::max(min_send_bitrate_kbps_, estimated_bitrate_bps_ / 1000) *
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kDefaultPaceMultiplier;
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alr_detector_->SetEstimatedBitrate(bitrate_bps);
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}
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void PacedSender::SetSendBitrateLimits(int min_send_bitrate_bps,
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int padding_bitrate) {
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CriticalSectionScoped cs(critsect_.get());
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min_send_bitrate_kbps_ = min_send_bitrate_bps / 1000;
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pacing_bitrate_kbps_ =
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std::max(min_send_bitrate_kbps_, estimated_bitrate_bps_ / 1000) *
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kDefaultPaceMultiplier;
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max_padding_bitrate_kbps_ = padding_bitrate / 1000;
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padding_budget_->set_target_rate_kbps(
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std::min(estimated_bitrate_bps_ / 1000, max_padding_bitrate_kbps_));
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}
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void PacedSender::InsertPacket(RtpPacketSender::Priority priority,
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uint32_t ssrc,
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uint16_t sequence_number,
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int64_t capture_time_ms,
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size_t bytes,
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bool retransmission) {
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CriticalSectionScoped cs(critsect_.get());
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RTC_DCHECK(estimated_bitrate_bps_ > 0)
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<< "SetEstimatedBitrate must be called before InsertPacket.";
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int64_t now_ms = clock_->TimeInMilliseconds();
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prober_->OnIncomingPacket(bytes);
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if (capture_time_ms < 0)
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capture_time_ms = now_ms;
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packets_->Push(paced_sender::Packet(priority, ssrc, sequence_number,
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capture_time_ms, now_ms, bytes,
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retransmission, packet_counter_++));
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}
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int64_t PacedSender::ExpectedQueueTimeMs() const {
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CriticalSectionScoped cs(critsect_.get());
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RTC_DCHECK_GT(pacing_bitrate_kbps_, 0);
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return static_cast<int64_t>(packets_->SizeInBytes() * 8 /
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pacing_bitrate_kbps_);
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}
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rtc::Optional<int64_t> PacedSender::GetApplicationLimitedRegionStartTime()
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const {
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CriticalSectionScoped cs(critsect_.get());
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return alr_detector_->GetApplicationLimitedRegionStartTime();
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}
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size_t PacedSender::QueueSizePackets() const {
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CriticalSectionScoped cs(critsect_.get());
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return packets_->SizeInPackets();
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}
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int64_t PacedSender::QueueInMs() const {
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CriticalSectionScoped cs(critsect_.get());
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int64_t oldest_packet = packets_->OldestEnqueueTimeMs();
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if (oldest_packet == 0)
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return 0;
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return clock_->TimeInMilliseconds() - oldest_packet;
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}
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int64_t PacedSender::AverageQueueTimeMs() {
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CriticalSectionScoped cs(critsect_.get());
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packets_->UpdateQueueTime(clock_->TimeInMilliseconds());
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return packets_->AverageQueueTimeMs();
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}
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int64_t PacedSender::TimeUntilNextProcess() {
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CriticalSectionScoped cs(critsect_.get());
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if (prober_->IsProbing()) {
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int64_t ret = prober_->TimeUntilNextProbe(clock_->TimeInMilliseconds());
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if (ret >= 0)
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return ret;
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}
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int64_t elapsed_time_us = clock_->TimeInMicroseconds() - time_last_update_us_;
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int64_t elapsed_time_ms = (elapsed_time_us + 500) / 1000;
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return std::max<int64_t>(kMinPacketLimitMs - elapsed_time_ms, 0);
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}
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void PacedSender::Process() {
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int64_t now_us = clock_->TimeInMicroseconds();
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CriticalSectionScoped cs(critsect_.get());
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int64_t elapsed_time_ms = (now_us - time_last_update_us_ + 500) / 1000;
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time_last_update_us_ = now_us;
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int target_bitrate_kbps = pacing_bitrate_kbps_;
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// TODO(holmer): Remove the !paused_ check when issue 5307 has been fixed.
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if (!paused_ && elapsed_time_ms > 0) {
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size_t queue_size_bytes = packets_->SizeInBytes();
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if (queue_size_bytes > 0) {
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// Assuming equal size packets and input/output rate, the average packet
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// has avg_time_left_ms left to get queue_size_bytes out of the queue, if
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// time constraint shall be met. Determine bitrate needed for that.
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packets_->UpdateQueueTime(clock_->TimeInMilliseconds());
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int64_t avg_time_left_ms = std::max<int64_t>(
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1, kMaxQueueLengthMs - packets_->AverageQueueTimeMs());
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int min_bitrate_needed_kbps =
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static_cast<int>(queue_size_bytes * 8 / avg_time_left_ms);
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if (min_bitrate_needed_kbps > target_bitrate_kbps)
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target_bitrate_kbps = min_bitrate_needed_kbps;
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}
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media_budget_->set_target_rate_kbps(target_bitrate_kbps);
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elapsed_time_ms = std::min(kMaxIntervalTimeMs, elapsed_time_ms);
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UpdateBudgetWithElapsedTime(elapsed_time_ms);
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}
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bool is_probing = prober_->IsProbing();
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int probe_cluster_id = PacketInfo::kNotAProbe;
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size_t bytes_sent = 0;
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size_t recommended_probe_size = 0;
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if (is_probing) {
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probe_cluster_id = prober_->CurrentClusterId();
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recommended_probe_size = prober_->RecommendedMinProbeSize();
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}
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while (!packets_->Empty()) {
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// Since we need to release the lock in order to send, we first pop the
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// element from the priority queue but keep it in storage, so that we can
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// reinsert it if send fails.
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const paced_sender::Packet& packet = packets_->BeginPop();
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if (SendPacket(packet, probe_cluster_id)) {
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// Send succeeded, remove it from the queue.
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bytes_sent += packet.bytes;
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packets_->FinalizePop(packet);
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if (is_probing && bytes_sent > recommended_probe_size)
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break;
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} else {
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// Send failed, put it back into the queue.
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packets_->CancelPop(packet);
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break;
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}
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}
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// TODO(holmer): Remove the paused_ check when issue 5307 has been fixed.
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if (packets_->Empty() && !paused_) {
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// We can not send padding unless a normal packet has first been sent. If we
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// do, timestamps get messed up.
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if (packet_counter_ > 0) {
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int padding_needed =
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static_cast<int>(is_probing ? (recommended_probe_size - bytes_sent)
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: padding_budget_->bytes_remaining());
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if (padding_needed > 0)
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bytes_sent += SendPadding(padding_needed, probe_cluster_id);
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}
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}
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if (is_probing && bytes_sent > 0)
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prober_->ProbeSent(clock_->TimeInMilliseconds(), bytes_sent);
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alr_detector_->OnBytesSent(bytes_sent, now_us / 1000);
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}
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bool PacedSender::SendPacket(const paced_sender::Packet& packet,
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int probe_cluster_id) {
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// TODO(holmer): Because of this bug issue 5307 we have to send audio
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// packets even when the pacer is paused. Here we assume audio packets are
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// always high priority and that they are the only high priority packets.
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if (packet.priority != kHighPriority) {
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if (paused_)
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return false;
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if (media_budget_->bytes_remaining() == 0 &&
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probe_cluster_id == PacketInfo::kNotAProbe) {
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return false;
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}
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}
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critsect_->Leave();
|
|
const bool success = packet_sender_->TimeToSendPacket(
|
|
packet.ssrc, packet.sequence_number, packet.capture_time_ms,
|
|
packet.retransmission, probe_cluster_id);
|
|
critsect_->Enter();
|
|
|
|
if (success) {
|
|
// TODO(holmer): High priority packets should only be accounted for if we
|
|
// are allocating bandwidth for audio.
|
|
if (packet.priority != kHighPriority) {
|
|
// Update media bytes sent.
|
|
UpdateBudgetWithBytesSent(packet.bytes);
|
|
}
|
|
}
|
|
|
|
return success;
|
|
}
|
|
|
|
size_t PacedSender::SendPadding(size_t padding_needed, int probe_cluster_id) {
|
|
critsect_->Leave();
|
|
size_t bytes_sent =
|
|
packet_sender_->TimeToSendPadding(padding_needed, probe_cluster_id);
|
|
critsect_->Enter();
|
|
|
|
if (bytes_sent > 0) {
|
|
UpdateBudgetWithBytesSent(bytes_sent);
|
|
}
|
|
return bytes_sent;
|
|
}
|
|
|
|
void PacedSender::UpdateBudgetWithElapsedTime(int64_t delta_time_ms) {
|
|
media_budget_->IncreaseBudget(delta_time_ms);
|
|
padding_budget_->IncreaseBudget(delta_time_ms);
|
|
}
|
|
|
|
void PacedSender::UpdateBudgetWithBytesSent(size_t bytes_sent) {
|
|
media_budget_->UseBudget(bytes_sent);
|
|
padding_budget_->UseBudget(bytes_sent);
|
|
}
|
|
} // namespace webrtc
|