1 /* 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_PACING_BITRATE_PROBER_H_ 12 #define MODULES_PACING_BITRATE_PROBER_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include <queue> 18 19 #include "api/transport/field_trial_based_config.h" 20 #include "api/transport/network_types.h" 21 #include "rtc_base/experiments/field_trial_parser.h" 22 23 namespace webrtc { 24 class RtcEventLog; 25 26 struct BitrateProberConfig { 27 explicit BitrateProberConfig(const WebRtcKeyValueConfig* key_value_config); 28 BitrateProberConfig(const BitrateProberConfig&) = default; 29 BitrateProberConfig& operator=(const BitrateProberConfig&) = default; 30 ~BitrateProberConfig() = default; 31 32 // The minimum number probing packets used. 33 FieldTrialParameter<int> min_probe_packets_sent; 34 // A minimum interval between probes to allow scheduling to be feasible. 35 FieldTrialParameter<TimeDelta> min_probe_delta; 36 // The minimum probing duration. 37 FieldTrialParameter<TimeDelta> min_probe_duration; 38 // Maximum amount of time each probe can be delayed. 39 FieldTrialParameter<TimeDelta> max_probe_delay; 40 // If NextProbeTime() is called with a delay higher than specified by 41 // |max_probe_delay|, abort it. 42 FieldTrialParameter<bool> abort_delayed_probes; 43 }; 44 45 // Note that this class isn't thread-safe by itself and therefore relies 46 // on being protected by the caller. 47 class BitrateProber { 48 public: 49 explicit BitrateProber(const WebRtcKeyValueConfig& field_trials); 50 ~BitrateProber(); 51 52 void SetEnabled(bool enable); 53 54 // Returns true if the prober is in a probing session, i.e., it currently 55 // wants packets to be sent out according to the time returned by 56 // TimeUntilNextProbe(). is_probing()57 bool is_probing() const { return probing_state_ == ProbingState::kActive; } 58 59 // Initializes a new probing session if the prober is allowed to probe. Does 60 // not initialize the prober unless the packet size is large enough to probe 61 // with. 62 void OnIncomingPacket(DataSize packet_size); 63 64 // Create a cluster used to probe for |bitrate_bps| with |num_probes| number 65 // of probes. 66 void CreateProbeCluster(DataRate bitrate, Timestamp now, int cluster_id); 67 68 // Returns the time at which the next probe should be sent to get accurate 69 // probing. If probing is not desired at this time, Timestamp::PlusInfinity() 70 // will be returned. 71 // TODO(bugs.webrtc.org/11780): Remove |now| argument when old mode is gone. 72 Timestamp NextProbeTime(Timestamp now) const; 73 74 // Information about the current probing cluster. 75 absl::optional<PacedPacketInfo> CurrentCluster(Timestamp now); 76 77 // Returns the minimum number of bytes that the prober recommends for 78 // the next probe, or zero if not probing. 79 DataSize RecommendedMinProbeSize() const; 80 81 // Called to report to the prober that a probe has been sent. In case of 82 // multiple packets per probe, this call would be made at the end of sending 83 // the last packet in probe. |size| is the total size of all packets in probe. 84 void ProbeSent(Timestamp now, DataSize size); 85 86 private: 87 enum class ProbingState { 88 // Probing will not be triggered in this state at all times. 89 kDisabled, 90 // Probing is enabled and ready to trigger on the first packet arrival. 91 kInactive, 92 // Probe cluster is filled with the set of data rates to be probed and 93 // probes are being sent. 94 kActive, 95 // Probing is enabled, but currently suspended until an explicit trigger 96 // to start probing again. 97 kSuspended, 98 }; 99 100 // A probe cluster consists of a set of probes. Each probe in turn can be 101 // divided into a number of packets to accommodate the MTU on the network. 102 struct ProbeCluster { 103 PacedPacketInfo pace_info; 104 105 int sent_probes = 0; 106 int sent_bytes = 0; 107 Timestamp created_at = Timestamp::MinusInfinity(); 108 Timestamp started_at = Timestamp::MinusInfinity(); 109 int retries = 0; 110 }; 111 112 Timestamp CalculateNextProbeTime(const ProbeCluster& cluster) const; 113 114 ProbingState probing_state_; 115 116 // Probe bitrate per packet. These are used to compute the delta relative to 117 // the previous probe packet based on the size and time when that packet was 118 // sent. 119 std::queue<ProbeCluster> clusters_; 120 121 // Time the next probe should be sent when in kActive state. 122 Timestamp next_probe_time_; 123 124 int total_probe_count_; 125 int total_failed_probe_count_; 126 127 BitrateProberConfig config_; 128 }; 129 130 } // namespace webrtc 131 132 #endif // MODULES_PACING_BITRATE_PROBER_H_ 133