ProbingEstimator: Erase history based on time threshold

webrtc/modules/congestion_controller/probe_bitrate_estimator.cc

Index: webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
diff --git a/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc b/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
index 561fde939180b74e0cad8b606952487c984eabbd..edee61edb5fef0bf3eba8ca81530a89df1d83fdc 100644
--- a/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
+++ b/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
@@ -12,6 +12,7 @@
 
 #include <algorithm>
 
+#include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 
 namespace {
@@ -27,25 +28,17 @@ constexpr float kValidRatio = 1.2f;
 
 namespace webrtc {
 
-ProbingResult::ProbingResult() : bps(kNoEstimate), timestamp(0) {}
-
-ProbingResult::ProbingResult(int bps, int64_t timestamp)
-    : bps(bps), timestamp(timestamp) {}
-
-bool ProbingResult::valid() const {
-  return bps != kNoEstimate;
-}
-
 ProbeBitrateEstimator::ProbeBitrateEstimator() : last_valid_cluster_id_(0) {}
 
-ProbingResult ProbeBitrateEstimator::PacketFeedback(
-    const PacketInfo& packet_info) {
-  // If this is not a probing packet or if this probing packet
-  // belongs to an old cluster, do nothing.
-  if (packet_info.probe_cluster_id == PacketInfo::kNotAProbe ||
-      packet_info.probe_cluster_id < last_valid_cluster_id_) {
-    return ProbingResult();
-  }
+int ProbeBitrateEstimator::HandleProbeAndEstimateBitrate(
+    const PacketInfo& packet_info,
+    size_t min_clusters) {
+  RTC_DCHECK(packet_info.probe_cluster_id == PacketInfo::kNotAProbe);
+
+  // If this probing packet belongs to an old cluster, do nothing.
+  if (packet_info.probe_cluster_id < last_valid_cluster_id_)
+    return -1;
+  last_valid_cluster_id_ = packet_info.probe_cluster_id;

[philipel, 2016/08/12 13:51:42]

|last_valid_cluster_id_| tracks the last cluster with a valid estimate and at
this point we don't know if this will result in a valid cluster.

There is also a risk that we receive feedback in the wrong order which could
result in a valid probing attempt to be ignored.

 
   AggregatedCluster* cluster = &clusters_[packet_info.probe_cluster_id];
   cluster->first_send_ms =
@@ -59,13 +52,16 @@ ProbingResult ProbeBitrateEstimator::PacketFeedback(
   cluster->size += packet_info.payload_size * 8;
   cluster->num_probes += 1;
 
+  if (cluster->num_probes < kMinNumProbesValidCluster)
+    return -1;
+
+  if (clusters_.size() < min_clusters)
+    return -1;
+
   // Clean up old clusters.
   while (clusters_.size() > kMaxNumSavedClusters)
     clusters_.erase(clusters_.begin());
 
-  if (cluster->num_probes < kMinNumProbesValidCluster)
-    return ProbingResult();
-
   float send_interval_ms = cluster->last_send_ms - cluster->first_send_ms;
   float receive_interval_ms =
       cluster->last_receive_ms - cluster->first_receive_ms;
@@ -83,8 +79,7 @@ ProbingResult ProbeBitrateEstimator::PacketFeedback(
                  << " [cluster id: " << packet_info.probe_cluster_id
                  << "] [send interval: " << send_interval_ms << " ms]"
                  << " [receive interval: " << receive_interval_ms << " ms]";
-
-    return ProbingResult();
+    return -1;
   }
   float send_bps = static_cast<float>(cluster->size) / send_interval_ms * 1000;
   float receive_bps =
@@ -101,12 +96,8 @@ ProbingResult ProbeBitrateEstimator::PacketFeedback(
                  << " [ratio: " << receive_bps / 1000 << " / "
                  << send_bps / 1000 << " = " << ratio << " > kValidRatio ("
                  << kValidRatio << ")]";
-
-    return ProbingResult();
+    return -1;
   }
-  // We have a valid estimate.
-  int result_bps = std::min(send_bps, receive_bps);
-  last_valid_cluster_id_ = packet_info.probe_cluster_id;
   LOG(LS_INFO) << "Probing successful"
                << " [cluster id: " << packet_info.probe_cluster_id
                << "] [send: " << cluster->size << " bytes / "
@@ -114,7 +105,18 @@ ProbingResult ProbeBitrateEstimator::PacketFeedback(
                << " [receive: " << cluster->size << " bytes / "
                << receive_interval_ms << " ms = " << receive_bps / 1000
                << " kb/s]";
+  cluster->bps = std::min(send_bps, receive_bps);
+  int highest_bps = HighestBitrateOnClusters();
+  clusters_.clear();
+  return highest_bps;
+}
 
-  return ProbingResult(result_bps, packet_info.arrival_time_ms);
+int ProbeBitrateEstimator::HighestBitrateOnClusters() {
+  int highest_bps = 0;
+  for (const auto& kv : clusters_) {
+    if (kv.second.bps > highest_bps)
+      highest_bps = kv.second.bps;
+  }
+  return highest_bps;
 }
 }  // namespace webrtc