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henrike@webrtc.org47be73b2014-05-13 18:00:261/*
Tim Psiaki3e255232015-09-14 17:38:082 * Copyright 2015 The WebRTC Project Authors. All rights reserved.
henrike@webrtc.org47be73b2014-05-13 18:00:263 *
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
kjellander19796962017-06-30 17:45:2111#include "webrtc/rtc_base/ratetracker.h"
Tim Psiaki3e255232015-09-14 17:38:0812
13#include <stddef.h>
14
15#include <algorithm>
16
kjellander19796962017-06-30 17:45:2117#include "webrtc/rtc_base/checks.h"
18#include "webrtc/rtc_base/timeutils.h"
henrike@webrtc.org47be73b2014-05-13 18:00:2619
20namespace rtc {
21
Honghai Zhang3f20ddb2016-05-06 18:29:1522static const int64_t kTimeUnset = -1;
23
24RateTracker::RateTracker(int64_t bucket_milliseconds, size_t bucket_count)
Tim Psiaki3e255232015-09-14 17:38:0825 : bucket_milliseconds_(bucket_milliseconds),
Peter Boström07e22e62015-10-07 10:23:2126 bucket_count_(bucket_count),
27 sample_buckets_(new size_t[bucket_count + 1]),
28 total_sample_count_(0u),
Honghai Zhang3f20ddb2016-05-06 18:29:1529 bucket_start_time_milliseconds_(kTimeUnset) {
30 RTC_CHECK(bucket_milliseconds > 0);
31 RTC_CHECK(bucket_count > 0);
henrike@webrtc.org47be73b2014-05-13 18:00:2632}
33
Tim Psiaki3e255232015-09-14 17:38:0834RateTracker::~RateTracker() {
35 delete[] sample_buckets_;
henrike@webrtc.org47be73b2014-05-13 18:00:2636}
37
Tim Psiaki3e255232015-09-14 17:38:0838double RateTracker::ComputeRateForInterval(
Honghai Zhang3f20ddb2016-05-06 18:29:1539 int64_t interval_milliseconds) const {
40 if (bucket_start_time_milliseconds_ == kTimeUnset) {
Tim Psiaki3e255232015-09-14 17:38:0841 return 0.0;
henrike@webrtc.org47be73b2014-05-13 18:00:2642 }
Honghai Zhang3f20ddb2016-05-06 18:29:1543 int64_t current_time = Time();
Tim Psiaki3e255232015-09-14 17:38:0844 // Calculate which buckets to sum up given the current time. If the time
45 // has passed to a new bucket then we have to skip some of the oldest buckets.
Honghai Zhang3f20ddb2016-05-06 18:29:1546 int64_t available_interval_milliseconds =
47 std::min(interval_milliseconds,
48 bucket_milliseconds_ * static_cast<int64_t>(bucket_count_));
Tim Psiaki3e255232015-09-14 17:38:0849 // number of old buckets (i.e. after the current bucket in the ring buffer)
50 // that are expired given our current time interval.
51 size_t buckets_to_skip;
52 // Number of milliseconds of the first bucket that are not a portion of the
53 // current interval.
Honghai Zhang3f20ddb2016-05-06 18:29:1554 int64_t milliseconds_to_skip;
Tim Psiaki3e255232015-09-14 17:38:0855 if (current_time >
56 initialization_time_milliseconds_ + available_interval_milliseconds) {
Honghai Zhang3f20ddb2016-05-06 18:29:1557 int64_t time_to_skip =
Peter Boström07e22e62015-10-07 10:23:2158 current_time - bucket_start_time_milliseconds_ +
Honghai Zhang3f20ddb2016-05-06 18:29:1559 static_cast<int64_t>(bucket_count_) * bucket_milliseconds_ -
Tim Psiaki3e255232015-09-14 17:38:0860 available_interval_milliseconds;
61 buckets_to_skip = time_to_skip / bucket_milliseconds_;
62 milliseconds_to_skip = time_to_skip % bucket_milliseconds_;
63 } else {
64 buckets_to_skip = bucket_count_ - current_bucket_;
Honghai Zhang3f20ddb2016-05-06 18:29:1565 milliseconds_to_skip = 0;
Tim Psiaki3e255232015-09-14 17:38:0866 available_interval_milliseconds =
67 TimeDiff(current_time, initialization_time_milliseconds_);
asapersson7ac0a742016-02-02 09:46:5368 // Let one bucket interval pass after initialization before reporting.
69 if (available_interval_milliseconds < bucket_milliseconds_) {
70 return 0.0;
71 }
Tim Psiaki3e255232015-09-14 17:38:0872 }
73 // If we're skipping all buckets that means that there have been no samples
74 // within the sampling interval so report 0.
Honghai Zhang3f20ddb2016-05-06 18:29:1575 if (buckets_to_skip > bucket_count_ || available_interval_milliseconds == 0) {
Tim Psiaki3e255232015-09-14 17:38:0876 return 0.0;
77 }
78 size_t start_bucket = NextBucketIndex(current_bucket_ + buckets_to_skip);
79 // Only count a portion of the first bucket according to how much of the
80 // first bucket is within the current interval.
Tim Psiakib04d4042015-11-11 00:34:5081 size_t total_samples = ((sample_buckets_[start_bucket] *
82 (bucket_milliseconds_ - milliseconds_to_skip)) +
83 (bucket_milliseconds_ >> 1)) /
Tim Psiaki3e255232015-09-14 17:38:0884 bucket_milliseconds_;
85 // All other buckets in the interval are counted in their entirety.
86 for (size_t i = NextBucketIndex(start_bucket);
87 i != NextBucketIndex(current_bucket_);
88 i = NextBucketIndex(i)) {
89 total_samples += sample_buckets_[i];
90 }
91 // Convert to samples per second.
Honghai Zhang3f20ddb2016-05-06 18:29:1592 return static_cast<double>(total_samples * 1000) /
93 static_cast<double>(available_interval_milliseconds);
henrike@webrtc.org47be73b2014-05-13 18:00:2694}
95
Tim Psiaki3e255232015-09-14 17:38:0896double RateTracker::ComputeTotalRate() const {
Honghai Zhang3f20ddb2016-05-06 18:29:1597 if (bucket_start_time_milliseconds_ == kTimeUnset) {
Tim Psiaki3e255232015-09-14 17:38:0898 return 0.0;
99 }
Honghai Zhang3f20ddb2016-05-06 18:29:15100 int64_t current_time = Time();
101 if (current_time <= initialization_time_milliseconds_) {
Tim Psiaki3e255232015-09-14 17:38:08102 return 0.0;
103 }
Honghai Zhang3f20ddb2016-05-06 18:29:15104 return static_cast<double>(total_sample_count_ * 1000) /
105 static_cast<double>(
106 TimeDiff(current_time, initialization_time_milliseconds_));
Tim Psiaki3e255232015-09-14 17:38:08107}
108
109size_t RateTracker::TotalSampleCount() const {
110 return total_sample_count_;
111}
112
113void RateTracker::AddSamples(size_t sample_count) {
114 EnsureInitialized();
Honghai Zhang3f20ddb2016-05-06 18:29:15115 int64_t current_time = Time();
Tim Psiaki3e255232015-09-14 17:38:08116 // Advance the current bucket as needed for the current time, and reset
117 // bucket counts as we advance.
Honghai Zhang3f20ddb2016-05-06 18:29:15118 for (size_t i = 0;
119 i <= bucket_count_ &&
120 current_time >= bucket_start_time_milliseconds_ + bucket_milliseconds_;
121 ++i) {
Tim Psiaki3e255232015-09-14 17:38:08122 bucket_start_time_milliseconds_ += bucket_milliseconds_;
123 current_bucket_ = NextBucketIndex(current_bucket_);
Honghai Zhang3f20ddb2016-05-06 18:29:15124 sample_buckets_[current_bucket_] = 0;
Tim Psiaki3e255232015-09-14 17:38:08125 }
126 // Ensure that bucket_start_time_milliseconds_ is updated appropriately if
127 // the entire buffer of samples has been expired.
128 bucket_start_time_milliseconds_ += bucket_milliseconds_ *
129 ((current_time - bucket_start_time_milliseconds_) / bucket_milliseconds_);
130 // Add all samples in the bucket that includes the current time.
131 sample_buckets_[current_bucket_] += sample_count;
132 total_sample_count_ += sample_count;
henrike@webrtc.org47be73b2014-05-13 18:00:26133}
134
Honghai Zhang3f20ddb2016-05-06 18:29:15135int64_t RateTracker::Time() const {
136 return rtc::TimeMillis();
henrike@webrtc.org47be73b2014-05-13 18:00:26137}
138
Tim Psiaki3e255232015-09-14 17:38:08139void RateTracker::EnsureInitialized() {
Honghai Zhang3f20ddb2016-05-06 18:29:15140 if (bucket_start_time_milliseconds_ == kTimeUnset) {
Tim Psiaki3e255232015-09-14 17:38:08141 initialization_time_milliseconds_ = Time();
142 bucket_start_time_milliseconds_ = initialization_time_milliseconds_;
Honghai Zhang3f20ddb2016-05-06 18:29:15143 current_bucket_ = 0;
Tim Psiaki3e255232015-09-14 17:38:08144 // We only need to initialize the first bucket because we reset buckets when
145 // current_bucket_ increments.
Honghai Zhang3f20ddb2016-05-06 18:29:15146 sample_buckets_[current_bucket_] = 0;
Tim Psiaki3e255232015-09-14 17:38:08147 }
148}
149
150size_t RateTracker::NextBucketIndex(size_t bucket_index) const {
151 return (bucket_index + 1u) % (bucket_count_ + 1u);
152}
153
henrike@webrtc.org47be73b2014-05-13 18:00:26154} // namespace rtc