Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2016 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             : #include "webrtc/modules/pacing/alr_detector.h"
      12             : 
      13             : #include "webrtc/base/checks.h"
      14             : #include "webrtc/base/logging.h"
      15             : 
      16             : namespace {
      17             : 
      18             : // Time period over which outgoing traffic is measured.
      19             : constexpr int kMeasurementPeriodMs = 500;
      20             : 
      21             : // Sent traffic percentage as a function of network capacity used to determine
      22             : // application-limited region. ALR region start when bandwidth usage drops below
      23             : // kAlrStartUsagePercent and ends when it raises above kAlrEndUsagePercent.
      24             : // NOTE: This is intentionally conservative at the moment until BW adjustments
      25             : // of application limited region is fine tuned.
      26             : constexpr int kAlrStartUsagePercent = 30;
      27             : constexpr int kAlrEndUsagePercent = 50;
      28             : 
      29             : }  // namespace
      30             : 
      31             : namespace webrtc {
      32             : 
      33           0 : AlrDetector::AlrDetector()
      34           0 :     : rate_(kMeasurementPeriodMs, RateStatistics::kBpsScale) {}
      35             : 
      36           0 : AlrDetector::~AlrDetector() {}
      37             : 
      38           0 : void AlrDetector::OnBytesSent(size_t bytes_sent, int64_t now_ms) {
      39           0 :   RTC_DCHECK(estimated_bitrate_bps_);
      40             : 
      41           0 :   rate_.Update(bytes_sent, now_ms);
      42           0 :   rtc::Optional<uint32_t> rate = rate_.Rate(now_ms);
      43           0 :   if (!rate)
      44           0 :     return;
      45             : 
      46           0 :   int percentage = static_cast<int>(*rate) * 100 / estimated_bitrate_bps_;
      47           0 :   if (percentage < kAlrStartUsagePercent && !alr_started_time_ms_) {
      48           0 :     alr_started_time_ms_ = rtc::Optional<int64_t>(now_ms);
      49           0 :   } else if (percentage > kAlrEndUsagePercent && alr_started_time_ms_) {
      50           0 :     alr_started_time_ms_ = rtc::Optional<int64_t>();
      51             :   }
      52             : }
      53             : 
      54           0 : void AlrDetector::SetEstimatedBitrate(int bitrate_bps) {
      55           0 :   RTC_DCHECK(bitrate_bps);
      56           0 :   estimated_bitrate_bps_ = bitrate_bps;
      57           0 : }
      58             : 
      59           0 : rtc::Optional<int64_t> AlrDetector::GetApplicationLimitedRegionStartTime()
      60             :     const {
      61           0 :   return alr_started_time_ms_;
      62             : }
      63             : 
      64             : }  // namespace webrtc