0182f85fd1
Previously AlrDetector was measuring amount of data sent in each 100ms interval and would enter ALR mode after 5 consecutive intervals when average bandwidth usage doesn't exceed 30% of the current estimate estimate. This meant that an application that uses only slightely more than 6% of total bandwidth may stay out of ALR mode, e.g. if it sends a frame of size BW*30ms every 0.5 seconds. 100ms is too short interval to average over, particularly when frame-rate falls below 10fps. With this change AlrDetector averages BW usage over last 500ms. It then enters ALR state when usage falls below 30% and exits it when usage exceeds 50%. BUG=webrtc:6332 R=philipel@webrtc.org, stefan@webrtc.org Review URL: https://codereview.webrtc.org/2503643003 . Cr-Commit-Position: refs/heads/master@{#15109}
112 lines
3.7 KiB
C++
112 lines
3.7 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/pacing/alr_detector.h"
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#include "webrtc/test/gtest.h"
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namespace {
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constexpr int kEstimatedBitrateBps = 300000;
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} // namespace
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namespace webrtc {
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class AlrDetectorTest : public testing::Test {
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public:
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void SetUp() override {
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alr_detector_.SetEstimatedBitrate(kEstimatedBitrateBps);
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}
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void SimulateOutgoingTraffic(int interval_ms, int usage_percentage) {
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const int kTimeStepMs = 10;
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for (int t = 0; t < interval_ms; t += kTimeStepMs) {
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now_ms += kTimeStepMs;
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alr_detector_.OnBytesSent(kEstimatedBitrateBps * usage_percentage *
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kTimeStepMs / (8 * 100 * 1000),
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now_ms);
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}
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int remainder_ms = interval_ms % kTimeStepMs;
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now_ms += remainder_ms;
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if (remainder_ms > 0) {
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alr_detector_.OnBytesSent(kEstimatedBitrateBps * usage_percentage *
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remainder_ms / (8 * 100 * 1000),
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remainder_ms);
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}
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}
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protected:
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AlrDetector alr_detector_;
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int64_t now_ms = 1;
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};
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TEST_F(AlrDetectorTest, AlrDetection) {
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// Start in non-ALR state.
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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// Stay in non-ALR state when usage is close to 100%.
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SimulateOutgoingTraffic(500, 90);
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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// Verify that we ALR starts when bitrate drops below 20%.
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SimulateOutgoingTraffic(500, 20);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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// Verify that we remain in ALR state while usage is still below 50%.
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SimulateOutgoingTraffic(500, 40);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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// Verify that ALR ends when usage is above 50%.
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SimulateOutgoingTraffic(500, 60);
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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}
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TEST_F(AlrDetectorTest, ShortSpike) {
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// Start in non-ALR state.
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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// Verify that we ALR starts when bitrate drops below 20%.
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SimulateOutgoingTraffic(500, 20);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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// Verify that we stay in ALR region even after a short bitrate spike.
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SimulateOutgoingTraffic(100, 150);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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SimulateOutgoingTraffic(200, 20);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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// ALR ends when usage is above 50%.
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SimulateOutgoingTraffic(500, 60);
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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}
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TEST_F(AlrDetectorTest, BandwidthEstimateChanges) {
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// Start in non-ALR state.
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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// ALR starts when bitrate drops below 20%.
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SimulateOutgoingTraffic(500, 20);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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// When bandwidth estimate drops the detector should stay in ALR mode and quit
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// it shortly afterwards as the sender continues sending the same amount of
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// traffic. This is necessary to ensure that ProbeController can still react
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// to the BWE drop by initiating a new probe.
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alr_detector_.SetEstimatedBitrate(kEstimatedBitrateBps / 5);
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EXPECT_TRUE(alr_detector_.InApplicationLimitedRegion());
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SimulateOutgoingTraffic(10, 20);
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EXPECT_FALSE(alr_detector_.InApplicationLimitedRegion());
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}
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} // namespace webrtc
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