1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "quiche/quic/core/quic_sustained_bandwidth_recorder.h"
6
7 #include "quiche/quic/core/quic_bandwidth.h"
8 #include "quiche/quic/core/quic_time.h"
9 #include "quiche/quic/platform/api/quic_logging.h"
10
11 namespace quic {
12
QuicSustainedBandwidthRecorder()13 QuicSustainedBandwidthRecorder::QuicSustainedBandwidthRecorder()
14 : has_estimate_(false),
15 is_recording_(false),
16 bandwidth_estimate_recorded_during_slow_start_(false),
17 bandwidth_estimate_(QuicBandwidth::Zero()),
18 max_bandwidth_estimate_(QuicBandwidth::Zero()),
19 max_bandwidth_timestamp_(0),
20 start_time_(QuicTime::Zero()) {}
21
RecordEstimate(bool in_recovery,bool in_slow_start,QuicBandwidth bandwidth,QuicTime estimate_time,QuicWallTime wall_time,QuicTime::Delta srtt)22 void QuicSustainedBandwidthRecorder::RecordEstimate(
23 bool in_recovery, bool in_slow_start, QuicBandwidth bandwidth,
24 QuicTime estimate_time, QuicWallTime wall_time, QuicTime::Delta srtt) {
25 if (in_recovery) {
26 is_recording_ = false;
27 QUIC_DVLOG(1) << "Stopped recording at: "
28 << estimate_time.ToDebuggingValue();
29 return;
30 }
31
32 if (!is_recording_) {
33 // This is the first estimate of a new recording period.
34 start_time_ = estimate_time;
35 is_recording_ = true;
36 QUIC_DVLOG(1) << "Started recording at: " << start_time_.ToDebuggingValue();
37 return;
38 }
39
40 // If we have been recording for at least 3 * srtt, then record the latest
41 // bandwidth estimate as a valid sustained bandwidth estimate.
42 if (estimate_time - start_time_ >= 3 * srtt) {
43 has_estimate_ = true;
44 bandwidth_estimate_recorded_during_slow_start_ = in_slow_start;
45 bandwidth_estimate_ = bandwidth;
46 QUIC_DVLOG(1) << "New sustained bandwidth estimate (KBytes/s): "
47 << bandwidth_estimate_.ToKBytesPerSecond();
48 }
49
50 // Check for an increase in max bandwidth.
51 if (bandwidth > max_bandwidth_estimate_) {
52 max_bandwidth_estimate_ = bandwidth;
53 max_bandwidth_timestamp_ = wall_time.ToUNIXSeconds();
54 QUIC_DVLOG(1) << "New max bandwidth estimate (KBytes/s): "
55 << max_bandwidth_estimate_.ToKBytesPerSecond();
56 }
57 }
58
59 } // namespace quic
60