Add an experiment for stricter pacing and ALR probing.

webrtc/modules/pacing/alr_detector.cc

 /*
  *  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 "webrtc/modules/pacing/alr_detector.h"
 
 #include <string>
 
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/format_macros.h"
 #include "webrtc/rtc_base/logging.h"
 #include "webrtc/rtc_base/timeutils.h"
 #include "webrtc/system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 
 const char* AlrDetector::kScreenshareProbingBweExperimentName =
     "WebRTC-ProbingScreenshareBwe";
+const char* AlrDetector::kStrictPacingAndProbingExperimentName =
+    "WebRTC-StrictPacingAndProbing";
 
 AlrDetector::AlrDetector()
     : bandwidth_usage_percent_(kDefaultAlrBandwidthUsagePercent),
       alr_start_budget_level_percent_(kDefaultAlrStartBudgetLevelPercent),
       alr_stop_budget_level_percent_(kDefaultAlrStopBudgetLevelPercent),
       alr_budget_(0, true) {
+  RTC_CHECK(
+      field_trial::FindFullName(kStrictPacingAndProbingExperimentName)
+          .empty() ||
+      field_trial::FindFullName(kScreenshareProbingBweExperimentName).empty());
   rtc::Optional<AlrExperimentSettings> experiment_settings =
-      ParseAlrSettingsFromFieldTrial();
+      ParseAlrSettingsFromFieldTrial(kScreenshareProbingBweExperimentName);
+  if (!experiment_settings) {
+    experiment_settings =
+        ParseAlrSettingsFromFieldTrial(kStrictPacingAndProbingExperimentName);
+  }
   if (experiment_settings) {
     alr_stop_budget_level_percent_ =
         experiment_settings->alr_stop_budget_level_percent;
     alr_start_budget_level_percent_ =
         experiment_settings->alr_start_budget_level_percent;
     bandwidth_usage_percent_ = experiment_settings->alr_bandwidth_usage_percent;
   }
 }
 
 AlrDetector::~AlrDetector() {}
@@ skipping 17 matching lines @@
   alr_budget_.set_target_rate_kbps(bitrate_bps * bandwidth_usage_percent_ /
                                    (1000 * 100));
 }
 
 rtc::Optional<int64_t> AlrDetector::GetApplicationLimitedRegionStartTime()
     const {
   return alr_started_time_ms_;
 }
 
 rtc::Optional<AlrDetector::AlrExperimentSettings>
-AlrDetector::ParseAlrSettingsFromFieldTrial() {
+AlrDetector::ParseAlrSettingsFromFieldTrial(const char* experiment_name) {
   rtc::Optional<AlrExperimentSettings> ret;
-  std::string group_name =
-      field_trial::FindFullName(kScreenshareProbingBweExperimentName);
+  std::string group_name = field_trial::FindFullName(experiment_name);
 
   const std::string kIgnoredSuffix = "_Dogfood";
   if (group_name.rfind(kIgnoredSuffix) ==
       group_name.length() - kIgnoredSuffix.length()) {
     group_name.resize(group_name.length() - kIgnoredSuffix.length());
   }
 
   if (group_name.empty())
     return ret;
 
   AlrExperimentSettings settings;
   if (sscanf(group_name.c_str(), "%f,%" PRId64 ",%d,%d,%d",
              &settings.pacing_factor, &settings.max_paced_queue_time,
              &settings.alr_bandwidth_usage_percent,
              &settings.alr_start_budget_level_percent,
              &settings.alr_stop_budget_level_percent) == 5) {
     ret.emplace(settings);
-    LOG(LS_INFO) << "Using screenshare ALR experiment settings: "
+    LOG(LS_INFO) << "Using ALR experiment settings: "
                     "pacing factor: "
                  << settings.pacing_factor << ", max pacer queue length: "
                  << settings.max_paced_queue_time
                  << ", ALR start bandwidth usage percent: "
                  << settings.alr_bandwidth_usage_percent
                  << ", ALR end budget level percent: "
                  << settings.alr_start_budget_level_percent
                  << ", ALR end budget level percent: "
                  << settings.alr_stop_budget_level_percent;
+  } else {
+    LOG(LS_INFO) << "Failed to parse ALR experiment: " << experiment_name;
   }
 
   return ret;
 }
 
 }  // namespace webrtc