Move shared files in net/quic/ into net/quic/core/

net/quic/congestion_control/rtt_stats.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "net/quic/congestion_control/rtt_stats.h"
-
-#include <cstdlib>  // std::abs
-
-#include "net/quic/quic_flags.h"
-
-using std::max;
-
-namespace net {
-
-namespace {
-
-// Default initial rtt used before any samples are received.
-const int kInitialRttMs = 100;
-const float kAlpha = 0.125f;
-const float kOneMinusAlpha = (1 - kAlpha);
-const float kBeta = 0.25f;
-const float kOneMinusBeta = (1 - kBeta);
-// 10-second window length for windowed min RTT.
-const int kMinRttWindowLengthMs = 10000;
-
-}  // namespace
-
-RttStats::RttStats()
-    : latest_rtt_(QuicTime::Delta::Zero()),
-      min_rtt_(QuicTime::Delta::Zero()),
-      smoothed_rtt_(QuicTime::Delta::Zero()),
-      previous_srtt_(QuicTime::Delta::Zero()),
-      mean_deviation_(QuicTime::Delta::Zero()),
-      initial_rtt_us_(kInitialRttMs * kNumMicrosPerMilli),
-      forced_windowed_min_rtt_(QuicTime::Delta::Zero()),
-      forced_windowed_min_rtt_time_(QuicTime::Zero()),
-      num_samples_for_forced_min_(0),
-      windowed_min_rtt_(
-          QuicTime::Delta::FromMilliseconds(kMinRttWindowLengthMs),
-          QuicTime::Delta::Zero(),
-          QuicTime::Zero()) {}
-
-void RttStats::SampleNewWindowedMinRtt(uint32_t num_samples) {
-  num_samples_for_forced_min_ = num_samples;
-  forced_windowed_min_rtt_ = QuicTime::Delta::Zero();
-  forced_windowed_min_rtt_time_ = QuicTime::Zero();
-}
-
-void RttStats::ExpireSmoothedMetrics() {
-  mean_deviation_ = max(mean_deviation_,
-                        QuicTime::Delta::FromMicroseconds(std::abs(
-                            (smoothed_rtt_ - latest_rtt_).ToMicroseconds())));
-  smoothed_rtt_ = max(smoothed_rtt_, latest_rtt_);
-}
-
-// Updates the RTT based on a new sample.
-void RttStats::UpdateRtt(QuicTime::Delta send_delta,
-                         QuicTime::Delta ack_delay,
-                         QuicTime now) {
-  if (send_delta.IsInfinite() || send_delta <= QuicTime::Delta::Zero()) {
-    LOG(WARNING) << "Ignoring measured send_delta, because it's is "
-                 << "either infinite, zero, or negative.  send_delta = "
-                 << send_delta.ToMicroseconds();
-    return;
-  }
-
-  // Update min_rtt_ first. min_rtt_ does not use an rtt_sample corrected for
-  // ack_delay but the raw observed send_delta, since poor clock granularity at
-  // the client may cause a high ack_delay to result in underestimation of the
-  // min_rtt_.
-  if (min_rtt_.IsZero() || min_rtt_ > send_delta) {
-    min_rtt_ = send_delta;
-  }
-  UpdateWindowedMinRtt(send_delta, now);
-
-  // Correct for ack_delay if information received from the peer results in a
-  // positive RTT sample. Otherwise, we use the send_delta as a reasonable
-  // measure for smoothed_rtt.
-  QuicTime::Delta rtt_sample(send_delta);
-  previous_srtt_ = smoothed_rtt_;
-
-  if (rtt_sample > ack_delay) {
-    rtt_sample = rtt_sample - ack_delay;
-  }
-  latest_rtt_ = rtt_sample;
-  // First time call.
-  if (smoothed_rtt_.IsZero()) {
-    smoothed_rtt_ = rtt_sample;
-    mean_deviation_ =
-        QuicTime::Delta::FromMicroseconds(rtt_sample.ToMicroseconds() / 2);
-  } else {
-    mean_deviation_ = QuicTime::Delta::FromMicroseconds(static_cast<int64_t>(
-        kOneMinusBeta * mean_deviation_.ToMicroseconds() +
-        kBeta * std::abs((smoothed_rtt_ - rtt_sample).ToMicroseconds())));
-    smoothed_rtt_ = kOneMinusAlpha * smoothed_rtt_ + kAlpha * rtt_sample;
-    DVLOG(1) << " smoothed_rtt(us):" << smoothed_rtt_.ToMicroseconds()
-             << " mean_deviation(us):" << mean_deviation_.ToMicroseconds();
-  }
-}
-
-void RttStats::UpdateWindowedMinRtt(QuicTime::Delta rtt_sample, QuicTime now) {
-  // Update windowed_min_rtt.
-  windowed_min_rtt_.Update(rtt_sample, now);
-  if (num_samples_for_forced_min_ <= 0) {
-    return;
-  }
-  // Reset windowed_min_rtt to the min of num_samples_for_forced_min_ samples.
-  if (forced_windowed_min_rtt_.IsZero() ||
-      rtt_sample <= forced_windowed_min_rtt_) {
-    forced_windowed_min_rtt_ = rtt_sample;
-    forced_windowed_min_rtt_time_ = now;
-  }
-  if (num_samples_for_forced_min_ == 1) {
-    windowed_min_rtt_.Reset(forced_windowed_min_rtt_,
-                            forced_windowed_min_rtt_time_);
-  }
-  --num_samples_for_forced_min_;
-}
-
-void RttStats::OnConnectionMigration() {
-  latest_rtt_ = QuicTime::Delta::Zero();
-  min_rtt_ = QuicTime::Delta::Zero();
-  smoothed_rtt_ = QuicTime::Delta::Zero();
-  mean_deviation_ = QuicTime::Delta::Zero();
-  initial_rtt_us_ = kInitialRttMs * kNumMicrosPerMilli;
-  num_samples_for_forced_min_ = 0;
-  windowed_min_rtt_.Reset(QuicTime::Delta::Zero(), QuicTime::Zero());
-}
-
-}  // namespace net