Report max interframe delay over window insdead of interframe delay sum
Maximum of interframe delay is calculated over moving window in
ReceiveStatistics proxy now and reported via GetStats. Name of a metric
is also changed.
BUG=none
Review-Url: https://codereview.webrtc.org/2995143002
Cr-Commit-Position: refs/heads/master@{#19463}
diff --git a/webrtc/rtc_base/BUILD.gn b/webrtc/rtc_base/BUILD.gn
index 60d1f57..477381a 100644
--- a/webrtc/rtc_base/BUILD.gn
+++ b/webrtc/rtc_base/BUILD.gn
@@ -135,6 +135,7 @@
"location.cc",
"location.h",
"mod_ops.h",
+ "moving_max_counter.h",
"onetimeevent.h",
"optional.cc",
"optional.h",
@@ -824,6 +825,7 @@
"logging_unittest.cc",
"md5digest_unittest.cc",
"mod_ops_unittest.cc",
+ "moving_max_counter_unittest.cc",
"onetimeevent_unittest.cc",
"optional_unittest.cc",
"pathutils_unittest.cc",
diff --git a/webrtc/rtc_base/moving_max_counter.h b/webrtc/rtc_base/moving_max_counter.h
new file mode 100644
index 0000000..907e9cf
--- /dev/null
+++ b/webrtc/rtc_base/moving_max_counter.h
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+
+#ifndef WEBRTC_RTC_BASE_MOVING_MAX_COUNTER_H_
+#define WEBRTC_RTC_BASE_MOVING_MAX_COUNTER_H_
+
+#include <stdint.h>
+
+#include <deque>
+#include <limits>
+#include <utility>
+
+#include "webrtc/rtc_base/checks.h"
+#include "webrtc/rtc_base/constructormagic.h"
+#include "webrtc/rtc_base/optional.h"
+
+namespace rtc {
+
+// Implements moving max: can add samples to it and calculate maximum over some
+// fixed moving window.
+//
+// Window size is configured at constructor.
+// Samples can be added with |Add()| and max over current window is returned by
+// |MovingMax|. |current_time_ms| in successive calls to Add and MovingMax
+// should never decrease as if it's a wallclock time.
+template <class T>
+class MovingMaxCounter {
+ public:
+ explicit MovingMaxCounter(int64_t window_length_ms);
+ // Advances the current time, and adds a new sample. The new current time must
+ // be at least as large as the old current time.
+ void Add(const T& sample, int64_t current_time_ms);
+ // Advances the current time, and returns the maximum sample in the time
+ // window ending at the current time. The new current time must be at least as
+ // large as the old current time.
+ rtc::Optional<T> Max(int64_t current_time_ms);
+ void Reset();
+
+ private:
+ // Throws out obsolete samples.
+ void RollWindow(int64_t new_time_ms);
+ const int64_t window_length_ms_;
+ // This deque stores (timestamp, sample) pairs in chronological order; new
+ // pairs are only ever added at the end. However, because they can't affect
+ // the Max() calculation, pairs older than window_length_ms_ are discarded,
+ // and if an older pair has a sample that's smaller than that of a younger
+ // pair, the older pair is discarded. As a result, the sequence of timestamps
+ // is strictly increasing, and the sequence of samples is strictly decreasing.
+ std::deque<std::pair<int64_t, T>> samples_;
+#if RTC_DCHECK_IS_ON
+ int64_t last_call_time_ms_ = std::numeric_limits<int64_t>::min();
+#endif
+ RTC_DISALLOW_COPY_AND_ASSIGN(MovingMaxCounter);
+};
+
+template <class T>
+MovingMaxCounter<T>::MovingMaxCounter(int64_t window_length_ms)
+ : window_length_ms_(window_length_ms) {}
+
+template <class T>
+void MovingMaxCounter<T>::Add(const T& sample, int64_t current_time_ms) {
+ RollWindow(current_time_ms);
+ // Remove samples that will never be maximum in any window: newly added sample
+ // will always be in all windows the previous samples are. Thus, smaller or
+ // equal samples could be removed. This will maintain the invariant - deque
+ // contains strictly decreasing sequence of values.
+ while (!samples_.empty() && samples_.back().second <= sample) {
+ samples_.pop_back();
+ }
+ // Add the new sample but only if there's no existing sample at the same time.
+ // Due to checks above, the already existing element will be larger, so the
+ // new sample will never be the maximum in any window.
+ if (samples_.empty() || samples_.back().first < current_time_ms) {
+ samples_.emplace_back(std::make_pair(current_time_ms, sample));
+ }
+}
+
+template <class T>
+rtc::Optional<T> MovingMaxCounter<T>::Max(int64_t current_time_ms) {
+ RollWindow(current_time_ms);
+ rtc::Optional<T> res;
+ if (!samples_.empty()) {
+ res.emplace(samples_.front().second);
+ }
+ return res;
+}
+
+template <class T>
+void MovingMaxCounter<T>::Reset() {
+ samples_.clear();
+}
+
+template <class T>
+void MovingMaxCounter<T>::RollWindow(int64_t new_time_ms) {
+#if RTC_DCHECK_IS_ON
+ RTC_DCHECK_GE(new_time_ms, last_call_time_ms_);
+ last_call_time_ms_ = new_time_ms;
+#endif
+ const int64_t window_begin_ms = new_time_ms - window_length_ms_;
+ auto it = samples_.begin();
+ while (it != samples_.end() && it->first < window_begin_ms) {
+ ++it;
+ }
+ samples_.erase(samples_.begin(), it);
+}
+
+} // namespace rtc
+
+#endif // WEBRTC_RTC_BASE_MOVING_MAX_COUNTER_H_
diff --git a/webrtc/rtc_base/moving_max_counter_unittest.cc b/webrtc/rtc_base/moving_max_counter_unittest.cc
new file mode 100644
index 0000000..54dbe7e
--- /dev/null
+++ b/webrtc/rtc_base/moving_max_counter_unittest.cc
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2017 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/rtc_base/moving_max_counter.h"
+#include "webrtc/test/gtest.h"
+
+TEST(MovingMaxCounter, ReportsMaximumInTheWindow) {
+ rtc::MovingMaxCounter<int> counter(100);
+ counter.Add(1, 1);
+ EXPECT_EQ(counter.Max(1), rtc::Optional<int>(1));
+ counter.Add(2, 30);
+ EXPECT_EQ(counter.Max(30), rtc::Optional<int>(2));
+ counter.Add(100, 60);
+ EXPECT_EQ(counter.Max(60), rtc::Optional<int>(100));
+ counter.Add(4, 70);
+ EXPECT_EQ(counter.Max(70), rtc::Optional<int>(100));
+ counter.Add(5, 90);
+ EXPECT_EQ(counter.Max(90), rtc::Optional<int>(100));
+}
+
+TEST(MovingMaxCounter, IgnoresOldElements) {
+ rtc::MovingMaxCounter<int> counter(100);
+ counter.Add(1, 1);
+ counter.Add(2, 30);
+ counter.Add(100, 60);
+ counter.Add(4, 70);
+ counter.Add(5, 90);
+ EXPECT_EQ(counter.Max(160), rtc::Optional<int>(100));
+ // 100 is now out of the window. Next maximum is 5.
+ EXPECT_EQ(counter.Max(161), rtc::Optional<int>(5));
+}
+
+TEST(MovingMaxCounter, HandlesEmptyWindow) {
+ rtc::MovingMaxCounter<int> counter(100);
+ counter.Add(123, 1);
+ EXPECT_TRUE(counter.Max(101).has_value());
+ EXPECT_FALSE(counter.Max(102).has_value());
+}
+
+TEST(MovingMaxCounter, HandlesSamplesWithEqualTimestamps) {
+ rtc::MovingMaxCounter<int> counter(100);
+ counter.Add(2, 30);
+ EXPECT_EQ(counter.Max(30), rtc::Optional<int>(2));
+ counter.Add(5, 30);
+ EXPECT_EQ(counter.Max(30), rtc::Optional<int>(5));
+ counter.Add(4, 30);
+ EXPECT_EQ(counter.Max(30), rtc::Optional<int>(5));
+ counter.Add(1, 90);
+ EXPECT_EQ(counter.Max(150), rtc::Optional<int>(1));
+}
