Reland "Moved congestion controller to goog_cc folder."
This is a reland of e6cefdf9c572cdce55ff0497ad6e516c76132ee8.
Original change's description:
> Moved congestion controller to goog_cc folder.
>
> Bug: webrtc:8415
> Change-Id: I2070da0cacf1dbfc4b6a89285af3e68fd03497ab
> Reviewed-on: https://webrtc-review.googlesource.com/43841
> Commit-Queue: Sebastian Jansson <srte@webrtc.org>
> Reviewed-by: Björn Terelius <terelius@webrtc.org>
> Reviewed-by: Stefan Holmer <stefan@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#21928}
Bug: webrtc:8415
Change-Id: Ib5cf8641466655d64ac80f720561817f4cab49a9
Reviewed-on: https://webrtc-review.googlesource.com/53062
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22244}diff --git a/modules/congestion_controller/goog_cc/probe_controller.cc b/modules/congestion_controller/goog_cc/probe_controller.cc
new file mode 100644
index 0000000..b257032
--- /dev/null
+++ b/modules/congestion_controller/goog_cc/probe_controller.cc
@@ -0,0 +1,310 @@
+/*
+ * Copyright (c) 2016 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/congestion_controller/goog_cc/probe_controller.h"
+
+#include <algorithm>
+#include <initializer_list>
+
+#include "rtc_base/logging.h"
+#include "rtc_base/numerics/safe_conversions.h"
+#include "system_wrappers/include/field_trial.h"
+#include "system_wrappers/include/metrics.h"
+
+namespace webrtc {
+namespace webrtc_cc {
+
+namespace {
+// The minimum number probing packets used.
+constexpr int kMinProbePacketsSent = 5;
+
+// The minimum probing duration in ms.
+constexpr int kMinProbeDurationMs = 15;
+
+// Maximum waiting time from the time of initiating probing to getting
+// the measured results back.
+constexpr int64_t kMaxWaitingTimeForProbingResultMs = 1000;
+
+// Value of |min_bitrate_to_probe_further_bps_| that indicates
+// further probing is disabled.
+constexpr int kExponentialProbingDisabled = 0;
+
+// Default probing bitrate limit. Applied only when the application didn't
+// specify max bitrate.
+constexpr int64_t kDefaultMaxProbingBitrateBps = 5000000;
+
+// Interval between probes when ALR periodic probing is enabled.
+constexpr int64_t kAlrPeriodicProbingIntervalMs = 5000;
+
+// Minimum probe bitrate percentage to probe further for repeated probes,
+// relative to the previous probe. For example, if 1Mbps probe results in
+// 80kbps, then we'll probe again at 1.6Mbps. In that case second probe won't be
+// sent if we get 600kbps from the first one.
+constexpr int kRepeatedProbeMinPercentage = 70;
+
+// If the bitrate drops to a factor |kBitrateDropThreshold| or lower
+// and we recover within |kBitrateDropTimeoutMs|, then we'll send
+// a probe at a fraction |kProbeFractionAfterDrop| of the original bitrate.
+constexpr double kBitrateDropThreshold = 0.66;
+constexpr int kBitrateDropTimeoutMs = 5000;
+constexpr double kProbeFractionAfterDrop = 0.85;
+
+// Timeout for probing after leaving ALR. If the bitrate drops significantly,
+// (as determined by the delay based estimator) and we leave ALR, then we will
+// send a probe if we recover within |kLeftAlrTimeoutMs| ms.
+constexpr int kAlrEndedTimeoutMs = 3000;
+
+// The expected uncertainty of probe result (as a fraction of the target probe
+// This is a limit on how often probing can be done when there is a BW
+// drop detected in ALR.
+constexpr int64_t kMinTimeBetweenAlrProbesMs = 5000;
+
+// bitrate). Used to avoid probing if the probe bitrate is close to our current
+// estimate.
+constexpr double kProbeUncertainty = 0.05;
+
+// Use probing to recover faster after large bitrate estimate drops.
+constexpr char kBweRapidRecoveryExperiment[] =
+ "WebRTC-BweRapidRecoveryExperiment";
+
+} // namespace
+
+ProbeController::ProbeController(NetworkControllerObserver* observer)
+ : observer_(observer), enable_periodic_alr_probing_(false) {
+ Reset(0);
+ in_rapid_recovery_experiment_ = webrtc::field_trial::FindFullName(
+ kBweRapidRecoveryExperiment) == "Enabled";
+}
+
+ProbeController::~ProbeController() {}
+
+void ProbeController::SetBitrates(int64_t min_bitrate_bps,
+ int64_t start_bitrate_bps,
+ int64_t max_bitrate_bps,
+ int64_t at_time_ms) {
+ if (start_bitrate_bps > 0) {
+ start_bitrate_bps_ = start_bitrate_bps;
+ estimated_bitrate_bps_ = start_bitrate_bps;
+ } else if (start_bitrate_bps_ == 0) {
+ start_bitrate_bps_ = min_bitrate_bps;
+ }
+
+ // The reason we use the variable |old_max_bitrate_pbs| is because we
+ // need to set |max_bitrate_bps_| before we call InitiateProbing.
+ int64_t old_max_bitrate_bps = max_bitrate_bps_;
+ max_bitrate_bps_ = max_bitrate_bps;
+
+ switch (state_) {
+ case State::kInit:
+ if (network_available_)
+ InitiateExponentialProbing(at_time_ms);
+ break;
+
+ case State::kWaitingForProbingResult:
+ break;
+
+ case State::kProbingComplete:
+ // If the new max bitrate is higher than the old max bitrate and the
+ // estimate is lower than the new max bitrate then initiate probing.
+ if (estimated_bitrate_bps_ != 0 &&
+ old_max_bitrate_bps < max_bitrate_bps_ &&
+ estimated_bitrate_bps_ < max_bitrate_bps_) {
+ // The assumption is that if we jump more than 20% in the bandwidth
+ // estimate or if the bandwidth estimate is within 90% of the new
+ // max bitrate then the probing attempt was successful.
+ mid_call_probing_succcess_threshold_ =
+ std::min(estimated_bitrate_bps_ * 1.2, max_bitrate_bps_ * 0.9);
+ mid_call_probing_waiting_for_result_ = true;
+ mid_call_probing_bitrate_bps_ = max_bitrate_bps_;
+
+ RTC_HISTOGRAM_COUNTS_10000("WebRTC.BWE.MidCallProbing.Initiated",
+ max_bitrate_bps_ / 1000);
+
+ InitiateProbing(at_time_ms, {max_bitrate_bps}, false);
+ }
+ break;
+ }
+}
+
+void ProbeController::OnNetworkAvailability(NetworkAvailability msg) {
+ network_available_ = msg.network_available;
+ if (network_available_ && state_ == State::kInit && start_bitrate_bps_ > 0)
+ InitiateExponentialProbing(msg.at_time.ms());
+}
+
+void ProbeController::InitiateExponentialProbing(int64_t at_time_ms) {
+ RTC_DCHECK(network_available_);
+ RTC_DCHECK(state_ == State::kInit);
+ RTC_DCHECK_GT(start_bitrate_bps_, 0);
+
+ // When probing at 1.8 Mbps ( 6x 300), this represents a threshold of
+ // 1.2 Mbps to continue probing.
+ InitiateProbing(at_time_ms, {3 * start_bitrate_bps_, 6 * start_bitrate_bps_},
+ true);
+}
+
+void ProbeController::SetEstimatedBitrate(int64_t bitrate_bps,
+ int64_t at_time_ms) {
+ int64_t now_ms = at_time_ms;
+
+ if (mid_call_probing_waiting_for_result_ &&
+ bitrate_bps >= mid_call_probing_succcess_threshold_) {
+ RTC_HISTOGRAM_COUNTS_10000("WebRTC.BWE.MidCallProbing.Success",
+ mid_call_probing_bitrate_bps_ / 1000);
+ RTC_HISTOGRAM_COUNTS_10000("WebRTC.BWE.MidCallProbing.ProbedKbps",
+ bitrate_bps / 1000);
+ mid_call_probing_waiting_for_result_ = false;
+ }
+
+ if (state_ == State::kWaitingForProbingResult) {
+ // Continue probing if probing results indicate channel has greater
+ // capacity.
+ RTC_LOG(LS_INFO) << "Measured bitrate: " << bitrate_bps
+ << " Minimum to probe further: "
+ << min_bitrate_to_probe_further_bps_;
+
+ if (min_bitrate_to_probe_further_bps_ != kExponentialProbingDisabled &&
+ bitrate_bps > min_bitrate_to_probe_further_bps_) {
+ // Double the probing bitrate.
+ InitiateProbing(now_ms, {2 * bitrate_bps}, true);
+ }
+ }
+
+ if (bitrate_bps < kBitrateDropThreshold * estimated_bitrate_bps_) {
+ time_of_last_large_drop_ms_ = now_ms;
+ bitrate_before_last_large_drop_bps_ = estimated_bitrate_bps_;
+ }
+
+ estimated_bitrate_bps_ = bitrate_bps;
+}
+
+void ProbeController::EnablePeriodicAlrProbing(bool enable) {
+ enable_periodic_alr_probing_ = enable;
+}
+
+void ProbeController::SetAlrStartTimeMs(
+ rtc::Optional<int64_t> alr_start_time_ms) {
+ alr_start_time_ms_ = alr_start_time_ms;
+}
+void ProbeController::SetAlrEndedTimeMs(int64_t alr_end_time_ms) {
+ alr_end_time_ms_.emplace(alr_end_time_ms);
+}
+
+void ProbeController::RequestProbe(int64_t at_time_ms) {
+ // Called once we have returned to normal state after a large drop in
+ // estimated bandwidth. The current response is to initiate a single probe
+ // session (if not already probing) at the previous bitrate.
+ //
+ // If the probe session fails, the assumption is that this drop was a
+ // real one from a competing flow or a network change.
+ bool in_alr = alr_start_time_ms_.has_value();
+ bool alr_ended_recently =
+ (alr_end_time_ms_.has_value() &&
+ at_time_ms - alr_end_time_ms_.value() < kAlrEndedTimeoutMs);
+ if (in_alr || alr_ended_recently || in_rapid_recovery_experiment_) {
+ if (state_ == State::kProbingComplete) {
+ uint32_t suggested_probe_bps =
+ kProbeFractionAfterDrop * bitrate_before_last_large_drop_bps_;
+ uint32_t min_expected_probe_result_bps =
+ (1 - kProbeUncertainty) * suggested_probe_bps;
+ int64_t time_since_drop_ms = at_time_ms - time_of_last_large_drop_ms_;
+ int64_t time_since_probe_ms = at_time_ms - last_bwe_drop_probing_time_ms_;
+ if (min_expected_probe_result_bps > estimated_bitrate_bps_ &&
+ time_since_drop_ms < kBitrateDropTimeoutMs &&
+ time_since_probe_ms > kMinTimeBetweenAlrProbesMs) {
+ RTC_LOG(LS_INFO) << "Detected big bandwidth drop, start probing.";
+ // Track how often we probe in response to bandwidth drop in ALR.
+ RTC_HISTOGRAM_COUNTS_10000(
+ "WebRTC.BWE.BweDropProbingIntervalInS",
+ (at_time_ms - last_bwe_drop_probing_time_ms_) / 1000);
+ InitiateProbing(at_time_ms, {suggested_probe_bps}, false);
+ last_bwe_drop_probing_time_ms_ = at_time_ms;
+ }
+ }
+ }
+}
+
+void ProbeController::Reset(int64_t at_time_ms) {
+ network_available_ = true;
+ state_ = State::kInit;
+ min_bitrate_to_probe_further_bps_ = kExponentialProbingDisabled;
+ time_last_probing_initiated_ms_ = 0;
+ estimated_bitrate_bps_ = 0;
+ start_bitrate_bps_ = 0;
+ max_bitrate_bps_ = 0;
+ int64_t now_ms = at_time_ms;
+ last_bwe_drop_probing_time_ms_ = now_ms;
+ alr_end_time_ms_.reset();
+ mid_call_probing_waiting_for_result_ = false;
+ time_of_last_large_drop_ms_ = now_ms;
+ bitrate_before_last_large_drop_bps_ = 0;
+}
+
+void ProbeController::Process(int64_t at_time_ms) {
+ int64_t now_ms = at_time_ms;
+
+ if (now_ms - time_last_probing_initiated_ms_ >
+ kMaxWaitingTimeForProbingResultMs) {
+ mid_call_probing_waiting_for_result_ = false;
+
+ if (state_ == State::kWaitingForProbingResult) {
+ RTC_LOG(LS_INFO) << "kWaitingForProbingResult: timeout";
+ state_ = State::kProbingComplete;
+ min_bitrate_to_probe_further_bps_ = kExponentialProbingDisabled;
+ }
+ }
+
+ if (state_ != State::kProbingComplete || !enable_periodic_alr_probing_)
+ return;
+
+ // Probe bandwidth periodically when in ALR state.
+ if (alr_start_time_ms_ && estimated_bitrate_bps_ > 0) {
+ int64_t next_probe_time_ms =
+ std::max(*alr_start_time_ms_, time_last_probing_initiated_ms_) +
+ kAlrPeriodicProbingIntervalMs;
+ if (now_ms >= next_probe_time_ms) {
+ InitiateProbing(now_ms, {estimated_bitrate_bps_ * 2}, true);
+ }
+ }
+}
+
+void ProbeController::InitiateProbing(
+ int64_t now_ms,
+ std::initializer_list<int64_t> bitrates_to_probe,
+ bool probe_further) {
+ for (int64_t bitrate : bitrates_to_probe) {
+ RTC_DCHECK_GT(bitrate, 0);
+ int64_t max_probe_bitrate_bps =
+ max_bitrate_bps_ > 0 ? max_bitrate_bps_ : kDefaultMaxProbingBitrateBps;
+ if (bitrate > max_probe_bitrate_bps) {
+ bitrate = max_probe_bitrate_bps;
+ probe_further = false;
+ }
+
+ ProbeClusterConfig config;
+ config.at_time = Timestamp::ms(now_ms);
+ config.target_data_rate = DataRate::bps(rtc::dchecked_cast<int>(bitrate));
+ config.target_duration = TimeDelta::ms(kMinProbeDurationMs);
+ config.target_probe_count = kMinProbePacketsSent;
+ observer_->OnProbeClusterConfig(config);
+ }
+ time_last_probing_initiated_ms_ = now_ms;
+ if (probe_further) {
+ state_ = State::kWaitingForProbingResult;
+ min_bitrate_to_probe_further_bps_ =
+ (*(bitrates_to_probe.end() - 1)) * kRepeatedProbeMinPercentage / 100;
+ } else {
+ state_ = State::kProbingComplete;
+ min_bitrate_to_probe_further_bps_ = kExponentialProbingDisabled;
+ }
+}
+
+} // namespace webrtc_cc
+} // namespace webrtc