// Copyright 2015 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/nqe/network_quality_estimator.h"
#include <algorithm>
#include <cmath>
#include <limits>
#include <utility>
#include "base/bind_helpers.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/metrics/histogram_base.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/sparse_histogram.h"
#include "base/rand_util.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/stringprintf.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/time/default_tick_clock.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "net/base/host_port_pair.h"
#include "net/base/load_flags.h"
#include "net/base/load_timing_info.h"
#include "net/base/network_interfaces.h"
#include "net/base/trace_constants.h"
#include "net/http/http_response_headers.h"
#include "net/http/http_response_info.h"
#include "net/http/http_status_code.h"
#include "net/nqe/network_quality_estimator_util.h"
#include "net/nqe/throughput_analyzer.h"
#include "net/nqe/weighted_observation.h"
#include "net/url_request/url_request.h"
#include "net/url_request/url_request_context.h"
#include "net/url_request/url_request_status.h"
#include "url/gurl.h"
#if defined(OS_ANDROID)
#include "net/android/cellular_signal_strength.h"
#include "net/android/network_library.h"
#endif // OS_ANDROID
namespace net {
class HostResolver;
namespace {
// Returns the histogram that should be used to record the given statistic.
// |max_limit| is the maximum value that can be stored in the histogram.
base::HistogramBase* GetHistogram(const std::string& statistic_name,
NetworkChangeNotifier::ConnectionType type,
int32_t max_limit) {
const base::LinearHistogram::Sample kLowerLimit = 1;
DCHECK_GT(max_limit, kLowerLimit);
const size_t kBucketCount = 50;
return base::Histogram::FactoryGet(
"NQE." + statistic_name +
NetworkQualityEstimatorParams::GetNameForConnectionType(type),
kLowerLimit, max_limit, kBucketCount,
base::HistogramBase::kUmaTargetedHistogramFlag);
}
NetworkQualityObservationSource ProtocolSourceToObservationSource(
SocketPerformanceWatcherFactory::Protocol protocol) {
switch (protocol) {
case SocketPerformanceWatcherFactory::PROTOCOL_TCP:
return NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
case SocketPerformanceWatcherFactory::PROTOCOL_QUIC:
return NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC;
}
NOTREACHED();
return NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
}
// Returns true if the scheme of the |request| is either HTTP or HTTPS.
bool RequestSchemeIsHTTPOrHTTPS(const URLRequest& request) {
return request.url().is_valid() && request.url().SchemeIsHTTPOrHTTPS();
}
// Returns the suffix of the histogram that should be used for recording the
// accuracy when the observed RTT is |observed_rtt|. The width of the intervals
// are in exponentially increasing order.
const char* GetHistogramSuffixObservedRTT(const base::TimeDelta& observed_rtt) {
const int32_t rtt_milliseconds = observed_rtt.InMilliseconds();
DCHECK_GE(rtt_milliseconds, 0);
// The values here should remain synchronized with the suffixes specified in
// histograms.xml.
static const char* const kSuffixes[] = {
"0_20", "20_60", "60_140", "140_300", "300_620",
"620_1260", "1260_2540", "2540_5100", "5100_Infinity"};
for (size_t i = 0; i < arraysize(kSuffixes) - 1; ++i) {
if (rtt_milliseconds <= (20 * (2 << i) - 20))
return kSuffixes[i];
}
return kSuffixes[arraysize(kSuffixes) - 1];
}
// Returns the suffix of the histogram that should be used for recording the
// accuracy when the observed throughput in kilobits per second is
// |observed_throughput_kbps|. The width of the intervals are in exponentially
// increasing order.
const char* GetHistogramSuffixObservedThroughput(
const int32_t& observed_throughput_kbps) {
DCHECK_GE(observed_throughput_kbps, 0);
// The values here should remain synchronized with the suffixes specified in
// histograms.xml.
static const char* const kSuffixes[] = {
"0_20", "20_60", "60_140", "140_300", "300_620",
"620_1260", "1260_2540", "2540_5100", "5100_Infinity"};
for (size_t i = 0; i < arraysize(kSuffixes) - 1; ++i) {
if (observed_throughput_kbps <= (20 * (2 << i) - 20))
return kSuffixes[i];
}
return kSuffixes[arraysize(kSuffixes) - 1];
}
// The least significant kTrimBits of the metric will be discarded. If the
// trimmed metric value is greater than what can be fit in kBitsPerMetric bits,
// then the largest value that can be represented in kBitsPerMetric bits is
// returned.
const int32_t kTrimBits = 5;
// Maximum number of bits in which one metric should fit. Restricting the amount
// of space allocated to a single metric makes it possile to fit multiple
// metrics in a single histogram sample, and ensures that all those metrics
// are recorded together as a single tuple.
const int32_t kBitsPerMetric = 7;
static_assert(32 >= kBitsPerMetric * 4,
"Four metrics would not fit in a 32-bit int");
// Trims the |metric| by removing the last kTrimBits, and then rounding down
// the |metric| such that the |metric| fits in kBitsPerMetric.
int32_t FitInKBitsPerMetricBits(int32_t metric) {
// Remove the last kTrimBits. This will allow the metric to fit within
// kBitsPerMetric while losing only the least significant bits.
DCHECK_LE(0, metric);
metric = metric >> kTrimBits;
// kLargestValuePossible is the largest value that can be recorded using
// kBitsPerMetric.
static const int32_t kLargestValuePossible = (1 << kBitsPerMetric) - 1;
if (metric > kLargestValuePossible) {
// Fit |metric| in kBitsPerMetric by clamping it down.
metric = kLargestValuePossible;
}
DCHECK_EQ(0, metric >> kBitsPerMetric) << metric;
return metric;
}
void RecordRTTAccuracy(base::StringPiece prefix,
int32_t metric,
base::TimeDelta measuring_duration,
base::TimeDelta observed_rtt) {
const std::string histogram_name =
base::StringPrintf("%s.EstimatedObservedDiff.%s.%d.%s", prefix.data(),
metric >= 0 ? "Positive" : "Negative",
static_cast<int32_t>(measuring_duration.InSeconds()),
GetHistogramSuffixObservedRTT(observed_rtt));
base::HistogramBase* histogram = base::Histogram::FactoryGet(
histogram_name, 1, 10 * 1000 /* 10 seconds */, 50 /* Number of buckets */,
base::HistogramBase::kUmaTargetedHistogramFlag);
histogram->Add(std::abs(metric));
}
void RecordThroughputAccuracy(const char* prefix,
int32_t metric,
base::TimeDelta measuring_duration,
int32_t observed_throughput_kbps) {
const std::string histogram_name = base::StringPrintf(
"%s.EstimatedObservedDiff.%s.%d.%s", prefix,
metric >= 0 ? "Positive" : "Negative",
static_cast<int32_t>(measuring_duration.InSeconds()),
GetHistogramSuffixObservedThroughput(observed_throughput_kbps));
base::HistogramBase* histogram = base::Histogram::FactoryGet(
histogram_name, 1, 1000 * 1000 /* 1 Gbps */, 50 /* Number of buckets */,
base::HistogramBase::kUmaTargetedHistogramFlag);
histogram->Add(std::abs(metric));
}
void RecordEffectiveConnectionTypeAccuracy(
const char* prefix,
int32_t metric,
base::TimeDelta measuring_duration,
EffectiveConnectionType observed_effective_connection_type) {
const std::string histogram_name =
base::StringPrintf("%s.EstimatedObservedDiff.%s.%d.%s", prefix,
metric >= 0 ? "Positive" : "Negative",
static_cast<int32_t>(measuring_duration.InSeconds()),
DeprecatedGetNameForEffectiveConnectionType(
observed_effective_connection_type));
base::HistogramBase* histogram = base::Histogram::FactoryGet(
histogram_name, 0, EFFECTIVE_CONNECTION_TYPE_LAST,
EFFECTIVE_CONNECTION_TYPE_LAST /* Number of buckets */,
base::HistogramBase::kUmaTargetedHistogramFlag);
histogram->Add(std::abs(metric));
}
} // namespace
NetworkQualityEstimator::NetworkQualityEstimator(
std::unique_ptr<ExternalEstimateProvider> external_estimates_provider,
std::unique_ptr<NetworkQualityEstimatorParams> params,
NetLog* net_log)
: params_(std::move(params)),
use_localhost_requests_(false),
disable_offline_check_(false),
tick_clock_(new base::DefaultTickClock()),
last_connection_change_(tick_clock_->NowTicks()),
current_network_id_(nqe::internal::NetworkID(
NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN,
std::string())),
http_downstream_throughput_kbps_observations_(
params_.get(),
tick_clock_.get(),
params_->weight_multiplier_per_second(),
params_->weight_multiplier_per_signal_strength_level()),
http_rtt_ms_observations_(
params_.get(),
tick_clock_.get(),
params_->weight_multiplier_per_second(),
params_->weight_multiplier_per_signal_strength_level()),
transport_rtt_ms_observations_(
params_.get(),
tick_clock_.get(),
params_->weight_multiplier_per_second(),
params_->weight_multiplier_per_signal_strength_level()),
effective_connection_type_at_last_main_frame_(
EFFECTIVE_CONNECTION_TYPE_UNKNOWN),
external_estimate_provider_(std::move(external_estimates_provider)),
effective_connection_type_recomputation_interval_(
base::TimeDelta::FromSeconds(10)),
rtt_observations_size_at_last_ect_computation_(0),
throughput_observations_size_at_last_ect_computation_(0),
transport_rtt_observation_count_last_ect_computation_(0),
new_rtt_observations_since_last_ect_computation_(0),
new_throughput_observations_since_last_ect_computation_(0),
increase_in_transport_rtt_updater_posted_(false),
effective_connection_type_(EFFECTIVE_CONNECTION_TYPE_UNKNOWN),
cached_estimate_applied_(false),
net_log_(NetLogWithSource::Make(
net_log,
net::NetLogSourceType::NETWORK_QUALITY_ESTIMATOR)),
event_creator_(net_log_),
weak_ptr_factory_(this) {
network_quality_store_.reset(new nqe::internal::NetworkQualityStore());
NetworkChangeNotifier::AddConnectionTypeObserver(this);
if (external_estimate_provider_) {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_AVAILABLE);
external_estimate_provider_->SetUpdatedEstimateDelegate(this);
} else {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_NOT_AVAILABLE);
}
throughput_analyzer_.reset(new nqe::internal::ThroughputAnalyzer(
this, params_.get(), base::ThreadTaskRunnerHandle::Get(),
base::Bind(&NetworkQualityEstimator::OnNewThroughputObservationAvailable,
base::Unretained(this)),
tick_clock_.get(), net_log_));
watcher_factory_.reset(new nqe::internal::SocketWatcherFactory(
base::ThreadTaskRunnerHandle::Get(),
params_->min_socket_watcher_notification_interval(),
base::Bind(&NetworkQualityEstimator::OnUpdatedTransportRTTAvailable,
base::Unretained(this)),
base::Bind(&NetworkQualityEstimator::ShouldSocketWatcherNotifyRTT,
base::Unretained(this)),
tick_clock_.get()));
// Record accuracy after a 15 second interval. The values used here must
// remain in sync with the suffixes specified in
// tools/metrics/histograms/histograms.xml.
accuracy_recording_intervals_.push_back(base::TimeDelta::FromSeconds(15));
GatherEstimatesForNextConnectionType();
}
void NetworkQualityEstimator::AddDefaultEstimates() {
DCHECK(thread_checker_.CalledOnValidThread());
if (!params_->add_default_platform_observations())
return;
if (params_->DefaultObservation(current_network_id_.type).http_rtt() !=
nqe::internal::InvalidRTT()) {
Observation rtt_observation(
params_->DefaultObservation(current_network_id_.type)
.http_rtt()
.InMilliseconds(),
tick_clock_->NowTicks(), INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_HTTP_FROM_PLATFORM);
AddAndNotifyObserversOfRTT(rtt_observation);
}
if (params_->DefaultObservation(current_network_id_.type).transport_rtt() !=
nqe::internal::InvalidRTT()) {
Observation rtt_observation(
params_->DefaultObservation(current_network_id_.type)
.transport_rtt()
.InMilliseconds(),
tick_clock_->NowTicks(), INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_TRANSPORT_FROM_PLATFORM);
AddAndNotifyObserversOfRTT(rtt_observation);
}
if (params_->DefaultObservation(current_network_id_.type)
.downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT) {
Observation throughput_observation(
params_->DefaultObservation(current_network_id_.type)
.downstream_throughput_kbps(),
tick_clock_->NowTicks(), INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_HTTP_FROM_PLATFORM);
AddAndNotifyObserversOfThroughput(throughput_observation);
}
}
NetworkQualityEstimator::~NetworkQualityEstimator() {
DCHECK(thread_checker_.CalledOnValidThread());
NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
}
const std::vector<base::TimeDelta>&
NetworkQualityEstimator::GetAccuracyRecordingIntervals() const {
DCHECK(thread_checker_.CalledOnValidThread());
return accuracy_recording_intervals_;
}
void NetworkQualityEstimator::NotifyStartTransaction(
const URLRequest& request) {
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request))
return;
// Update |estimated_quality_at_last_main_frame_| if this is a main frame
// request.
// TODO(tbansal): Refactor this to a separate method.
if (request.load_flags() & LOAD_MAIN_FRAME_DEPRECATED) {
base::TimeTicks now = tick_clock_->NowTicks();
last_main_frame_request_ = now;
ComputeEffectiveConnectionType();
effective_connection_type_at_last_main_frame_ = effective_connection_type_;
estimated_quality_at_last_main_frame_ = network_quality_;
// Post the tasks which will run in the future and record the estimation
// accuracy based on the observations received between now and the time of
// task execution. Posting the task at different intervals makes it
// possible to measure the accuracy by comparing the estimate with the
// observations received over intervals of varying durations.
for (const base::TimeDelta& measuring_delay :
GetAccuracyRecordingIntervals()) {
base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
base::Bind(&NetworkQualityEstimator::RecordAccuracyAfterMainFrame,
weak_ptr_factory_.GetWeakPtr(), measuring_delay),
measuring_delay);
}
} else {
MaybeComputeEffectiveConnectionType();
}
throughput_analyzer_->NotifyStartTransaction(request);
}
void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
TRACE_EVENT0(kNetTracingCategory,
"NetworkQualityEstimator::NotifyHeadersReceived");
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request) ||
!RequestProvidesRTTObservation(request)) {
return;
}
if (request.load_flags() & LOAD_MAIN_FRAME_DEPRECATED) {
ComputeEffectiveConnectionType();
RecordMetricsOnMainFrameRequest();
MaybeQueryExternalEstimateProvider();
}
LoadTimingInfo load_timing_info;
request.GetLoadTimingInfo(&load_timing_info);
// If the load timing info is unavailable, it probably means that the request
// did not go over the network.
if (load_timing_info.send_start.is_null() ||
load_timing_info.receive_headers_end.is_null()) {
return;
}
DCHECK(!request.response_info().was_cached);
// Duration between when the resource was requested and when the response
// headers were received.
const base::TimeDelta observed_http_rtt =
load_timing_info.receive_headers_end - load_timing_info.send_start;
if (observed_http_rtt <= base::TimeDelta())
return;
DCHECK_GE(observed_http_rtt, base::TimeDelta());
Observation http_rtt_observation(observed_http_rtt.InMilliseconds(),
tick_clock_->NowTicks(), signal_strength_,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP);
AddAndNotifyObserversOfRTT(http_rtt_observation);
throughput_analyzer_->NotifyBytesRead(request);
}
void NetworkQualityEstimator::NotifyBytesRead(const URLRequest& request) {
DCHECK(thread_checker_.CalledOnValidThread());
throughput_analyzer_->NotifyBytesRead(request);
}
void NetworkQualityEstimator::RecordAccuracyAfterMainFrame(
base::TimeDelta measuring_duration) const {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_EQ(0, measuring_duration.InMilliseconds() % 1000);
DCHECK(ContainsValue(GetAccuracyRecordingIntervals(), measuring_duration));
const base::TimeTicks now = tick_clock_->NowTicks();
// Return if the time since |last_main_frame_request_| is less than
// |measuring_duration|. This may happen if another main frame request started
// during last |measuring_duration|. Returning here ensures that we do not
// take inaccurate readings.
if (now - last_main_frame_request_ < measuring_duration)
return;
// Return if the time since |last_main_frame_request_| is off by a factor of
// 2. This can happen if the task is executed much later than its scheduled
// time. Returning here ensures that we do not take inaccurate readings.
if (now - last_main_frame_request_ > 2 * measuring_duration)
return;
// Do not record accuracy if there was a connection change since the last main
// frame request.
if (last_main_frame_request_ <= last_connection_change_)
return;
base::TimeDelta recent_http_rtt;
if (!GetRecentHttpRTT(last_main_frame_request_, &recent_http_rtt))
recent_http_rtt = nqe::internal::InvalidRTT();
if (estimated_quality_at_last_main_frame_.http_rtt() !=
nqe::internal::InvalidRTT() &&
recent_http_rtt != nqe::internal::InvalidRTT()) {
const int estimated_observed_diff_milliseconds =
estimated_quality_at_last_main_frame_.http_rtt().InMilliseconds() -
recent_http_rtt.InMilliseconds();
RecordRTTAccuracy("NQE.Accuracy.HttpRTT",
estimated_observed_diff_milliseconds, measuring_duration,
recent_http_rtt);
}
base::TimeDelta recent_transport_rtt;
if (estimated_quality_at_last_main_frame_.transport_rtt() !=
nqe::internal::InvalidRTT() &&
GetRecentTransportRTT(last_main_frame_request_, &recent_transport_rtt,
nullptr)) {
const int estimated_observed_diff_milliseconds =
estimated_quality_at_last_main_frame_.transport_rtt().InMilliseconds() -
recent_transport_rtt.InMilliseconds();
RecordRTTAccuracy("NQE.Accuracy.TransportRTT",
estimated_observed_diff_milliseconds, measuring_duration,
recent_transport_rtt);
}
int32_t recent_downstream_throughput_kbps;
if (estimated_quality_at_last_main_frame_.downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT &&
GetRecentDownlinkThroughputKbps(last_main_frame_request_,
&recent_downstream_throughput_kbps)) {
const int estimated_observed_diff =
estimated_quality_at_last_main_frame_.downstream_throughput_kbps() -
recent_downstream_throughput_kbps;
RecordThroughputAccuracy("NQE.Accuracy.DownstreamThroughputKbps",
estimated_observed_diff, measuring_duration,
recent_downstream_throughput_kbps);
}
EffectiveConnectionType recent_effective_connection_type =
GetRecentEffectiveConnectionType(last_main_frame_request_);
if (effective_connection_type_at_last_main_frame_ !=
EFFECTIVE_CONNECTION_TYPE_UNKNOWN &&
recent_effective_connection_type != EFFECTIVE_CONNECTION_TYPE_UNKNOWN) {
const int estimated_observed_diff =
static_cast<int>(effective_connection_type_at_last_main_frame_) -
static_cast<int>(recent_effective_connection_type);
RecordEffectiveConnectionTypeAccuracy(
"NQE.Accuracy.EffectiveConnectionType", estimated_observed_diff,
measuring_duration, recent_effective_connection_type);
}
// Add histogram to evaluate the accuracy of the external estimate provider.
if (external_estimate_provider_quality_.http_rtt() !=
nqe::internal::InvalidRTT() &&
recent_http_rtt != nqe::internal::InvalidRTT()) {
const int estimated_observed_diff_milliseconds =
external_estimate_provider_quality_.http_rtt().InMilliseconds() -
recent_http_rtt.InMilliseconds();
RecordRTTAccuracy("NQE.ExternalEstimateProvider.RTT.Accuracy",
estimated_observed_diff_milliseconds, measuring_duration,
recent_http_rtt);
}
}
void NetworkQualityEstimator::NotifyRequestCompleted(const URLRequest& request,
int net_error) {
TRACE_EVENT0(kNetTracingCategory,
"NetworkQualityEstimator::NotifyRequestCompleted");
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request))
return;
throughput_analyzer_->NotifyRequestCompleted(request);
RecordCorrelationMetric(request, net_error);
}
void NetworkQualityEstimator::RecordCorrelationMetric(const URLRequest& request,
int net_error) const {
DCHECK(thread_checker_.CalledOnValidThread());
// The histogram is recorded randomly to reduce overhead involved with sparse
// histograms. Furthermore, recording the correlation on each request is
// unnecessary.
if (RandDouble() >= params_->correlation_uma_logging_probability())
return;
if (request.response_info().was_cached ||
!request.response_info().network_accessed) {
return;
}
LoadTimingInfo load_timing_info;
request.GetLoadTimingInfo(&load_timing_info);
// If the load timing info is unavailable, it probably means that the request
// did not go over the network.
if (load_timing_info.send_start.is_null() ||
load_timing_info.receive_headers_end.is_null()) {
return;
}
// Record UMA only for successful requests that have completed.
if (net_error != OK)
return;
if (!request.response_info().headers.get() ||
request.response_info().headers->response_code() != HTTP_OK) {
return;
}
if (load_timing_info.receive_headers_end < last_main_frame_request_)
return;
// Use the system clock instead of |tick_clock_| to compare the current
// timestamp with the |load_timing_info| timestamp since the latter is set by
// the system clock, and may be different from |tick_clock_| in tests.
const base::TimeTicks now = base::TimeTicks::Now();
// Record UMA only for requests that started recently.
if (now - last_main_frame_request_ > base::TimeDelta::FromSeconds(15))
return;
if (last_connection_change_ >= last_main_frame_request_)
return;
DCHECK_GE(now, load_timing_info.send_start);
int32_t rtt = 0;
if (estimated_quality_at_last_main_frame_.downstream_throughput_kbps() ==
nqe::internal::INVALID_RTT_THROUGHPUT) {
return;
}
if (UseTransportRTT()) {
if (estimated_quality_at_last_main_frame_.transport_rtt() ==
nqe::internal::InvalidRTT()) {
return;
}
rtt = FitInKBitsPerMetricBits(
estimated_quality_at_last_main_frame_.transport_rtt().InMilliseconds());
} else {
if (estimated_quality_at_last_main_frame_.http_rtt() ==
nqe::internal::InvalidRTT()) {
return;
}
rtt = FitInKBitsPerMetricBits(
estimated_quality_at_last_main_frame_.http_rtt().InMilliseconds());
}
const int32_t downstream_throughput = FitInKBitsPerMetricBits(
estimated_quality_at_last_main_frame_.downstream_throughput_kbps());
const int32_t resource_load_time = FitInKBitsPerMetricBits(
(now - load_timing_info.send_start).InMilliseconds());
int64_t resource_size = (request.GetTotalReceivedBytes() * 8) / 1024;
if (resource_size >= (1 << kBitsPerMetric)) {
// Too large resource size (at least 128 Kb).
return;
}
DCHECK_EQ(
0, (rtt | downstream_throughput | resource_load_time | resource_size) >>
kBitsPerMetric);
// First 32 - (4* kBitsPerMetric) of the sample are unset. Next
// kBitsPerMetric of the sample contain |rtt|. Next
// kBitsPerMetric contain |downstream_throughput|. Next kBitsPerMetric
// contain |resource_load_time|. And, the last kBitsPerMetric
// contain |resource_size|.
int32_t sample = rtt;
sample = (sample << kBitsPerMetric) | downstream_throughput;
sample = (sample << kBitsPerMetric) | resource_load_time;
sample = (sample << kBitsPerMetric) | resource_size;
UMA_HISTOGRAM_SPARSE_SLOWLY("NQE.Correlation.ResourceLoadTime.0Kb_128Kb",
sample);
}
void NetworkQualityEstimator::NotifyURLRequestDestroyed(
const URLRequest& request) {
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request))
return;
throughput_analyzer_->NotifyRequestCompleted(request);
}
void NetworkQualityEstimator::AddRTTObserver(RTTObserver* rtt_observer) {
DCHECK(thread_checker_.CalledOnValidThread());
rtt_observer_list_.AddObserver(rtt_observer);
}
void NetworkQualityEstimator::RemoveRTTObserver(RTTObserver* rtt_observer) {
DCHECK(thread_checker_.CalledOnValidThread());
rtt_observer_list_.RemoveObserver(rtt_observer);
}
void NetworkQualityEstimator::AddThroughputObserver(
ThroughputObserver* throughput_observer) {
DCHECK(thread_checker_.CalledOnValidThread());
throughput_observer_list_.AddObserver(throughput_observer);
}
void NetworkQualityEstimator::RemoveThroughputObserver(
ThroughputObserver* throughput_observer) {
DCHECK(thread_checker_.CalledOnValidThread());
throughput_observer_list_.RemoveObserver(throughput_observer);
}
SocketPerformanceWatcherFactory*
NetworkQualityEstimator::GetSocketPerformanceWatcherFactory() {
DCHECK(thread_checker_.CalledOnValidThread());
return watcher_factory_.get();
}
void NetworkQualityEstimator::SetUseLocalHostRequestsForTesting(
bool use_localhost_requests) {
DCHECK(thread_checker_.CalledOnValidThread());
use_localhost_requests_ = use_localhost_requests;
watcher_factory_->SetUseLocalHostRequestsForTesting(use_localhost_requests_);
throughput_analyzer_->SetUseLocalHostRequestsForTesting(
use_localhost_requests_);
}
void NetworkQualityEstimator::SetUseSmallResponsesForTesting(
bool use_small_responses) {
DCHECK(thread_checker_.CalledOnValidThread());
params_->SetUseSmallResponsesForTesting(use_small_responses);
}
void NetworkQualityEstimator::DisableOfflineCheckForTesting(
bool disable_offline_check) {
DCHECK(thread_checker_.CalledOnValidThread());
disable_offline_check_ = disable_offline_check;
network_quality_store_->DisableOfflineCheckForTesting(disable_offline_check_);
}
void NetworkQualityEstimator::ReportEffectiveConnectionTypeForTesting(
EffectiveConnectionType effective_connection_type) {
DCHECK(thread_checker_.CalledOnValidThread());
event_creator_.MaybeAddNetworkQualityChangedEventToNetLog(
effective_connection_type_,
params_->TypicalNetworkQuality(effective_connection_type));
for (auto& observer : effective_connection_type_observer_list_)
observer.OnEffectiveConnectionTypeChanged(effective_connection_type);
network_quality_store_->Add(current_network_id_,
nqe::internal::CachedNetworkQuality(
tick_clock_->NowTicks(), network_quality_,
effective_connection_type));
}
void NetworkQualityEstimator::ReportRTTsAndThroughputForTesting(
base::TimeDelta http_rtt,
base::TimeDelta transport_rtt,
int32_t downstream_throughput_kbps) {
DCHECK(thread_checker_.CalledOnValidThread());
for (auto& observer : rtt_and_throughput_estimates_observer_list_)
observer.OnRTTOrThroughputEstimatesComputed(http_rtt, transport_rtt,
downstream_throughput_kbps);
}
bool NetworkQualityEstimator::RequestProvidesRTTObservation(
const URLRequest& request) const {
DCHECK(thread_checker_.CalledOnValidThread());
bool private_network_request = nqe::internal::IsPrivateHost(
request.context()->host_resolver(),
HostPortPair(request.url().host(), request.url().EffectiveIntPort()));
return (use_localhost_requests_ || !private_network_request) &&
// Verify that response headers are received, so it can be ensured that
// response is not cached.
!request.response_info().response_time.is_null() &&
!request.was_cached() &&
request.creation_time() >= last_connection_change_ &&
request.method() == "GET";
}
void NetworkQualityEstimator::RecordExternalEstimateProviderMetrics(
NQEExternalEstimateProviderStatus status) const {
UMA_HISTOGRAM_ENUMERATION("NQE.ExternalEstimateProviderStatus", status,
EXTERNAL_ESTIMATE_PROVIDER_STATUS_BOUNDARY);
}
void NetworkQualityEstimator::OnConnectionTypeChanged(
NetworkChangeNotifier::ConnectionType type) {
DCHECK(thread_checker_.CalledOnValidThread());
RecordMetricsOnConnectionTypeChanged();
// Write the estimates of the previous network to the cache.
network_quality_store_->Add(
current_network_id_, nqe::internal::CachedNetworkQuality(
last_effective_connection_type_computation_,
network_quality_, effective_connection_type_));
// Clear the local state.
last_connection_change_ = tick_clock_->NowTicks();
http_downstream_throughput_kbps_observations_.Clear();
http_rtt_ms_observations_.Clear();
transport_rtt_ms_observations_.Clear();
if (external_estimate_provider_)
external_estimate_provider_->ClearCachedEstimate();
#if defined(OS_ANDROID)
if (params_->weight_multiplier_per_signal_strength_level() < 1.0 &&
NetworkChangeNotifier::IsConnectionCellular(current_network_id_.type)) {
bool signal_strength_available =
min_signal_strength_since_connection_change_ &&
max_signal_strength_since_connection_change_;
UMA_HISTOGRAM_BOOLEAN("NQE.CellularSignalStrength.LevelAvailable",
signal_strength_available);
if (signal_strength_available) {
UMA_HISTOGRAM_COUNTS_100(
"NQE.CellularSignalStrength.LevelDifference",
max_signal_strength_since_connection_change_.value() -
min_signal_strength_since_connection_change_.value());
}
}
#endif // OS_ANDROID
signal_strength_.reset();
min_signal_strength_since_connection_change_.reset();
max_signal_strength_since_connection_change_.reset();
network_quality_ = nqe::internal::NetworkQuality();
effective_connection_type_ = EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
effective_connection_type_at_last_main_frame_ =
EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
rtt_observations_size_at_last_ect_computation_ = 0;
throughput_observations_size_at_last_ect_computation_ = 0;
new_rtt_observations_since_last_ect_computation_ = 0;
new_throughput_observations_since_last_ect_computation_ = 0;
transport_rtt_observation_count_last_ect_computation_ = 0;
last_socket_watcher_rtt_notification_ = base::TimeTicks();
estimated_quality_at_last_main_frame_ = nqe::internal::NetworkQuality();
cached_estimate_applied_ = false;
GatherEstimatesForNextConnectionType();
throughput_analyzer_->OnConnectionTypeChanged();
}
void NetworkQualityEstimator::GatherEstimatesForNextConnectionType() {
DCHECK(thread_checker_.CalledOnValidThread());
// Update the local state as part of preparation for the new connection.
current_network_id_ = GetCurrentNetworkID();
RecordNetworkIDAvailability();
MaybeQueryExternalEstimateProvider();
// Read any cached estimates for the new network. If cached estimates are
// unavailable, add the default estimates.
if (!ReadCachedNetworkQualityEstimate())
AddDefaultEstimates();
ComputeEffectiveConnectionType();
}
void NetworkQualityEstimator::MaybeQueryExternalEstimateProvider() const {
// Query the external estimate provider on certain connection types. Once the
// updated estimates are available, OnUpdatedEstimateAvailable will be called
// by |external_estimate_provider_| with updated estimates.
if (!external_estimate_provider_ ||
current_network_id_.type == NetworkChangeNotifier::CONNECTION_NONE ||
current_network_id_.type == NetworkChangeNotifier::CONNECTION_UNKNOWN ||
current_network_id_.type == NetworkChangeNotifier::CONNECTION_ETHERNET ||
current_network_id_.type == NetworkChangeNotifier::CONNECTION_BLUETOOTH) {
return;
}
if (cached_estimate_applied_) {
// Do not use external estimate provider if a local cached value is
// available.
return;
}
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERIED);
external_estimate_provider_->Update();
}
void NetworkQualityEstimator::UpdateSignalStrength() {
DCHECK(thread_checker_.CalledOnValidThread());
signal_strength_.reset();
#if defined(OS_ANDROID)
if (params_->weight_multiplier_per_signal_strength_level() >= 1.0)
return;
if (!NetworkChangeNotifier::IsConnectionCellular(current_network_id_.type))
return;
signal_strength_ =
android::cellular_signal_strength::GetSignalStrengthLevel();
if (!signal_strength_)
return;
min_signal_strength_since_connection_change_ =
std::min(min_signal_strength_since_connection_change_.value_or(INT32_MAX),
signal_strength_.value());
max_signal_strength_since_connection_change_ =
std::max(max_signal_strength_since_connection_change_.value_or(INT32_MIN),
signal_strength_.value());
#endif // OS_ANDROID
}
void NetworkQualityEstimator::RecordMetricsOnConnectionTypeChanged() const {
DCHECK(thread_checker_.CalledOnValidThread());
base::TimeDelta rtt;
if (GetRecentHttpRTT(base::TimeTicks(), &rtt)) {
// Add the 50th percentile value.
base::HistogramBase* rtt_percentile =
GetHistogram("RTT.Percentile50.", current_network_id_.type, 10 * 1000);
rtt_percentile->Add(rtt.InMilliseconds());
// Add the remaining percentile values.
static const int kPercentiles[] = {0, 10, 90, 100};
for (size_t i = 0; i < arraysize(kPercentiles); ++i) {
rtt = GetRTTEstimateInternal(
base::TimeTicks(), base::Optional<Statistic>(),
nqe::internal::ObservationCategory::kHttp, kPercentiles[i], nullptr);
rtt_percentile = GetHistogram(
"RTT.Percentile" + base::IntToString(kPercentiles[i]) + ".",
current_network_id_.type, 10 * 1000); // 10 seconds
rtt_percentile->Add(rtt.InMilliseconds());
}
}
if (GetRecentTransportRTT(base::TimeTicks(), &rtt, nullptr)) {
// Add the 50th percentile value.
base::HistogramBase* transport_rtt_percentile = GetHistogram(
"TransportRTT.Percentile50.", current_network_id_.type, 10 * 1000);
transport_rtt_percentile->Add(rtt.InMilliseconds());
// Add the remaining percentile values.
static const int kPercentiles[] = {0, 10, 90, 100};
for (size_t i = 0; i < arraysize(kPercentiles); ++i) {
rtt =
GetRTTEstimateInternal(base::TimeTicks(), base::Optional<Statistic>(),
nqe::internal::ObservationCategory::kTransport,
kPercentiles[i], nullptr);
transport_rtt_percentile = GetHistogram(
"TransportRTT.Percentile" + base::IntToString(kPercentiles[i]) + ".",
current_network_id_.type, 10 * 1000); // 10 seconds
transport_rtt_percentile->Add(rtt.InMilliseconds());
}
}
}
void NetworkQualityEstimator::RecordNetworkIDAvailability() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (current_network_id_.type ==
NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI ||
NetworkChangeNotifier::IsConnectionCellular(current_network_id_.type)) {
UMA_HISTOGRAM_BOOLEAN("NQE.NetworkIdAvailable",
!current_network_id_.id.empty());
}
}
void NetworkQualityEstimator::RecordMetricsOnMainFrameRequest() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (estimated_quality_at_last_main_frame_.http_rtt() !=
nqe::internal::InvalidRTT()) {
// Add the 50th percentile value.
UMA_HISTOGRAM_TIMES("NQE.MainFrame.RTT.Percentile50",
estimated_quality_at_last_main_frame_.http_rtt());
}
UMA_HISTOGRAM_BOOLEAN("NQE.EstimateAvailable.MainFrame.RTT",
estimated_quality_at_last_main_frame_.http_rtt() !=
nqe::internal::InvalidRTT());
if (estimated_quality_at_last_main_frame_.transport_rtt() !=
nqe::internal::InvalidRTT()) {
// Add the 50th percentile value.
UMA_HISTOGRAM_TIMES("NQE.MainFrame.TransportRTT.Percentile50",
estimated_quality_at_last_main_frame_.transport_rtt());
}
UMA_HISTOGRAM_BOOLEAN("NQE.EstimateAvailable.MainFrame.TransportRTT",
estimated_quality_at_last_main_frame_.transport_rtt() !=
nqe::internal::InvalidRTT());
if (estimated_quality_at_last_main_frame_.downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT) {
// Add the 50th percentile value.
UMA_HISTOGRAM_COUNTS_1M(
"NQE.MainFrame.Kbps.Percentile50",
estimated_quality_at_last_main_frame_.downstream_throughput_kbps());
}
UMA_HISTOGRAM_BOOLEAN(
"NQE.EstimateAvailable.MainFrame.Kbps",
estimated_quality_at_last_main_frame_.downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT);
UMA_HISTOGRAM_ENUMERATION("NQE.MainFrame.EffectiveConnectionType",
effective_connection_type_at_last_main_frame_,
EFFECTIVE_CONNECTION_TYPE_LAST);
}
void NetworkQualityEstimator::ComputeBandwidthDelayProduct() {
DCHECK(thread_checker_.CalledOnValidThread());
// Reset the bandwidth delay product to prevent stale values being returned.
bandwidth_delay_product_kbits_.reset();
// Record the bandwidth delay product (BDP) from the 80 percentile throughput
// and the 20 percentile transport RTT. Percentiles are reversed for
// throughput. The reason for using the 20 percentile transport RTT is to get
// an estimate of the true RTT sans the queueing delay. The minimum value of
// transport RTT was not used because it is likely to be noisy. For
// throughput, the 80 percentile value is considered to get an estimate of the
// maximum bandwidth when there is no congestion. The maximum value of
// observed throughput was not used because it is likely to be noisy.
base::TimeDelta transport_rtt = GetRTTEstimateInternal(
base::TimeTicks(), base::Optional<Statistic>(),
nqe::internal::ObservationCategory::kTransport, 20, nullptr);
if (transport_rtt == nqe::internal::InvalidRTT())
return;
int32_t downlink_throughput_kbps =
GetDownlinkThroughputKbpsEstimateInternal(base::TimeTicks(), 20);
if (downlink_throughput_kbps == nqe::internal::INVALID_RTT_THROUGHPUT)
return;
bandwidth_delay_product_kbits_ =
(downlink_throughput_kbps * transport_rtt.InMilliseconds()) / 1000;
// Record UMA histograms.
UMA_HISTOGRAM_TIMES("NQE.BDPComputationTransportRTT.OnECTComputation",
transport_rtt);
UMA_HISTOGRAM_COUNTS_1M("NQE.BDPComputationKbps.OnECTComputation",
downlink_throughput_kbps);
UMA_HISTOGRAM_COUNTS_1M("NQE.BDPKbits.OnECTComputation",
bandwidth_delay_product_kbits_.value());
}
void NetworkQualityEstimator::IncreaseInTransportRTTUpdater() {
DCHECK(thread_checker_.CalledOnValidThread());
increase_in_transport_rtt_ = ComputeIncreaseInTransportRTT();
// Stop the timer if there was no recent data and |increase_in_transport_rtt_|
// could not be computed. This is fine because |increase_in_transport_rtt| can
// only be computed if there is recent transport RTT data, and the timer is
// restarted when there is a new observation.
if (!increase_in_transport_rtt_) {
increase_in_transport_rtt_updater_posted_ = false;
return;
}
increase_in_transport_rtt_updater_posted_ = true;
base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
FROM_HERE,
base::Bind(&NetworkQualityEstimator::IncreaseInTransportRTTUpdater,
weak_ptr_factory_.GetWeakPtr()),
params_->increase_in_transport_rtt_logging_interval());
}
base::Optional<int32_t> NetworkQualityEstimator::ComputeIncreaseInTransportRTT()
const {
DCHECK(thread_checker_.CalledOnValidThread());
base::TimeTicks now = tick_clock_->NowTicks();
// The time after which the observations are considered to be recent enough to
// be a good proxy for the current level of congestion.
base::TimeTicks recent_start_time = now - params_->recent_time_threshold();
// Get the median transport RTT observed over the last 5 seconds for each
// remote host. This is an estimate of the current RTT which will be compared
// to the baseline obtained from historical data to detect an increase in RTT.
std::map<nqe::internal::IPHash, int32_t> recent_median_rtts;
std::map<nqe::internal::IPHash, size_t> recent_observation_counts;
transport_rtt_ms_observations_.GetPercentileForEachHostWithCounts(
recent_start_time, 50, base::nullopt, &recent_median_rtts,
&recent_observation_counts);
if (recent_median_rtts.empty())
return base::nullopt;
// The time after which the observations are used to calculate the baseline.
// This is needed because the general network characteristics could have
// changed over time.
base::TimeTicks history_start_time =
now - params_->historical_time_threshold();
// Create a set of the remote hosts seen in the recent observations so that
// the data can be filtered while calculating the percentiles.
std::set<nqe::internal::IPHash> recent_hosts_set;
for (const auto& recent_median_rtts_for_host : recent_median_rtts)
recent_hosts_set.insert(recent_median_rtts_for_host.first);
// Get the minimum transport RTT observed over 1 minute for each remote host.
// This is an estimate of the true RTT which will be used as a baseline value
// to detect an increase in RTT. The minimum value is used here because the
// observed values cannot be lower than the true RTT. The median is used for
// the recent data to reduce noise in the calculation.
std::map<nqe::internal::IPHash, int32_t> historical_min_rtts;
std::map<nqe::internal::IPHash, size_t> historical_observation_counts;
transport_rtt_ms_observations_.GetPercentileForEachHostWithCounts(
history_start_time, 0, recent_hosts_set, &historical_min_rtts,
&historical_observation_counts);
// Calculate the total observation counts for the hosts common to the recent
// data and the historical data.
size_t total_historical_count = 0;
size_t total_recent_count = 0;
for (const auto& recent_median_rtts_for_host : recent_median_rtts) {
nqe::internal::IPHash host = recent_median_rtts_for_host.first;
total_historical_count += historical_observation_counts[host];
total_recent_count += recent_observation_counts[host];
}
// Compute the increases in transport RTT for each remote host. Also compute
// the weight for each remote host based on the number of observations.
double total_weight = 0.0;
std::vector<nqe::internal::WeightedObservation> weighted_rtts;
for (auto& host : recent_hosts_set) {
// The relative weight signifies the amount of confidence in the data. The
// weight is higher if there were more observations. A regularization term
// of |1 / recent_hosts_set.size()| is added so that if one particular
// remote host has a lot of observations, the results do not get skewed.
double weight =
1.0 / recent_hosts_set.size() +
std::min(static_cast<double>(recent_observation_counts[host]) /
total_recent_count,
static_cast<double>(historical_observation_counts[host]) /
total_historical_count);
weighted_rtts.push_back(nqe::internal::WeightedObservation(
recent_median_rtts[host] - historical_min_rtts[host], weight));
total_weight += weight;
}
// Sort the increases in RTT for percentile computation.
std::sort(weighted_rtts.begin(), weighted_rtts.end());
// Calculate the weighted 50th percentile increase in transport RTT.
double desired_weight = 0.5 * total_weight;
for (nqe::internal::WeightedObservation wo : weighted_rtts) {
desired_weight -= wo.weight;
if (desired_weight <= 0)
return wo.value;
}
// Calculation will reach here when the 50th percentile is the last value.
return weighted_rtts.back().value;
}
void NetworkQualityEstimator::ComputeEffectiveConnectionType() {
DCHECK(thread_checker_.CalledOnValidThread());
UpdateSignalStrength();
const base::TimeTicks now = tick_clock_->NowTicks();
const EffectiveConnectionType past_type = effective_connection_type_;
last_effective_connection_type_computation_ = now;
base::TimeDelta http_rtt = nqe::internal::InvalidRTT();
base::TimeDelta transport_rtt = nqe::internal::InvalidRTT();
int32_t downstream_throughput_kbps = nqe::internal::INVALID_RTT_THROUGHPUT;
effective_connection_type_ =
GetRecentEffectiveConnectionTypeAndNetworkQuality(
base::TimeTicks(), &http_rtt, &transport_rtt,
&downstream_throughput_kbps,
&transport_rtt_observation_count_last_ect_computation_);
network_quality_ = nqe::internal::NetworkQuality(http_rtt, transport_rtt,
downstream_throughput_kbps);
ComputeBandwidthDelayProduct();
UMA_HISTOGRAM_ENUMERATION("NQE.EffectiveConnectionType.OnECTComputation",
effective_connection_type_,
EFFECTIVE_CONNECTION_TYPE_LAST);
if (network_quality_.http_rtt() != nqe::internal::InvalidRTT()) {
UMA_HISTOGRAM_TIMES("NQE.RTT.OnECTComputation",
network_quality_.http_rtt());
}
if (network_quality_.transport_rtt() != nqe::internal::InvalidRTT()) {
UMA_HISTOGRAM_TIMES("NQE.TransportRTT.OnECTComputation",
network_quality_.transport_rtt());
}
if (network_quality_.downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT) {
UMA_HISTOGRAM_COUNTS_1M("NQE.Kbps.OnECTComputation",
network_quality_.downstream_throughput_kbps());
}
NotifyObserversOfRTTOrThroughputComputed();
if (past_type != effective_connection_type_)
NotifyObserversOfEffectiveConnectionTypeChanged();
event_creator_.MaybeAddNetworkQualityChangedEventToNetLog(
effective_connection_type_, network_quality_);
rtt_observations_size_at_last_ect_computation_ =
http_rtt_ms_observations_.Size() + transport_rtt_ms_observations_.Size();
throughput_observations_size_at_last_ect_computation_ =
http_downstream_throughput_kbps_observations_.Size();
new_rtt_observations_since_last_ect_computation_ = 0;
new_throughput_observations_since_last_ect_computation_ = 0;
}
EffectiveConnectionType NetworkQualityEstimator::GetEffectiveConnectionType()
const {
DCHECK(thread_checker_.CalledOnValidThread());
return effective_connection_type_;
}
EffectiveConnectionType
NetworkQualityEstimator::GetRecentEffectiveConnectionType(
const base::TimeTicks& start_time) const {
DCHECK(thread_checker_.CalledOnValidThread());
base::TimeDelta http_rtt = nqe::internal::InvalidRTT();
base::TimeDelta transport_rtt = nqe::internal::InvalidRTT();
int32_t downstream_throughput_kbps = nqe::internal::INVALID_RTT_THROUGHPUT;
return GetRecentEffectiveConnectionTypeAndNetworkQuality(
start_time, &http_rtt, &transport_rtt, &downstream_throughput_kbps,
nullptr);
}
EffectiveConnectionType
NetworkQualityEstimator::GetRecentEffectiveConnectionTypeAndNetworkQuality(
const base::TimeTicks& start_time,
base::TimeDelta* http_rtt,
base::TimeDelta* transport_rtt,
int32_t* downstream_throughput_kbps,
size_t* transport_rtt_observation_count) const {
DCHECK(thread_checker_.CalledOnValidThread());
if (params_->GetEffectiveConnectionTypeAlgorithm() ==
NetworkQualityEstimatorParams::EffectiveConnectionTypeAlgorithm::
HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT) {
return GetRecentEffectiveConnectionTypeUsingMetrics(
start_time,
NetworkQualityEstimator::MetricUsage::
MUST_BE_USED /* http_rtt_metric */,
NetworkQualityEstimator::MetricUsage::
DO_NOT_USE /* transport_rtt_metric */,
NetworkQualityEstimator::MetricUsage::
USE_IF_AVAILABLE /* downstream_throughput_kbps_metric */,
http_rtt, transport_rtt, downstream_throughput_kbps,
transport_rtt_observation_count);
}
if (params_->GetEffectiveConnectionTypeAlgorithm() ==
NetworkQualityEstimatorParams::EffectiveConnectionTypeAlgorithm::
TRANSPORT_RTT_OR_DOWNSTREAM_THROUGHOUT) {
return GetRecentEffectiveConnectionTypeUsingMetrics(
start_time,
NetworkQualityEstimator::MetricUsage::DO_NOT_USE /* http_rtt_metric */,
NetworkQualityEstimator::MetricUsage::
USE_IF_AVAILABLE /* transport_rtt_metric */,
NetworkQualityEstimator::MetricUsage::
USE_IF_AVAILABLE /* downstream_throughput_kbps_metric */,
http_rtt, transport_rtt, downstream_throughput_kbps,
transport_rtt_observation_count);
}
// Add additional algorithms here.
NOTREACHED();
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
bool NetworkQualityEstimator::UseTransportRTT() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (params_->GetEffectiveConnectionTypeAlgorithm() ==
NetworkQualityEstimatorParams::EffectiveConnectionTypeAlgorithm::
HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT) {
return false;
}
if (params_->GetEffectiveConnectionTypeAlgorithm() ==
NetworkQualityEstimatorParams::EffectiveConnectionTypeAlgorithm::
TRANSPORT_RTT_OR_DOWNSTREAM_THROUGHOUT) {
return true;
}
// Add additional algorithms here.
NOTREACHED();
return false;
}
EffectiveConnectionType
NetworkQualityEstimator::GetRecentEffectiveConnectionTypeUsingMetrics(
const base::TimeTicks& start_time,
NetworkQualityEstimator::MetricUsage http_rtt_metric,
NetworkQualityEstimator::MetricUsage transport_rtt_metric,
NetworkQualityEstimator::MetricUsage downstream_throughput_kbps_metric,
base::TimeDelta* http_rtt,
base::TimeDelta* transport_rtt,
int32_t* downstream_throughput_kbps,
size_t* transport_rtt_observation_count) const {
DCHECK(thread_checker_.CalledOnValidThread());
*http_rtt = nqe::internal::InvalidRTT();
*transport_rtt = nqe::internal::InvalidRTT();
*downstream_throughput_kbps = nqe::internal::INVALID_RTT_THROUGHPUT;
if (params_->forced_effective_connection_type()) {
*http_rtt = params_
->TypicalNetworkQuality(
params_->forced_effective_connection_type().value())
.http_rtt();
*transport_rtt =
params_
->TypicalNetworkQuality(
params_->forced_effective_connection_type().value())
.transport_rtt();
*downstream_throughput_kbps =
params_
->TypicalNetworkQuality(
params_->forced_effective_connection_type().value())
.downstream_throughput_kbps();
return params_->forced_effective_connection_type().value();
}
// If the device is currently offline, then return
// EFFECTIVE_CONNECTION_TYPE_OFFLINE.
if (current_network_id_.type == NetworkChangeNotifier::CONNECTION_NONE &&
!disable_offline_check_) {
return EFFECTIVE_CONNECTION_TYPE_OFFLINE;
}
if (!GetRecentHttpRTT(start_time, http_rtt))
*http_rtt = nqe::internal::InvalidRTT();
if (!GetRecentTransportRTT(start_time, transport_rtt,
transport_rtt_observation_count)) {
*transport_rtt = nqe::internal::InvalidRTT();
}
if (*http_rtt != nqe::internal::InvalidRTT() &&
*transport_rtt != nqe::internal::InvalidRTT()) {
// Use transport RTT to clamp the HTTP RTT between lower and upper bounds.
// To improve accuracy, the transport RTT estimate is used only when the
// transport RTT estimate was computed using at least 5 observations.
if (transport_rtt_observation_count_last_ect_computation_ >=
params_->http_rtt_transport_rtt_min_count()) {
if (params_->lower_bound_http_rtt_transport_rtt_multiplier() > 0) {
*http_rtt = std::max(
*http_rtt,
*transport_rtt *
params_->lower_bound_http_rtt_transport_rtt_multiplier());
}
if (params_->upper_bound_http_rtt_transport_rtt_multiplier() > 0) {
*http_rtt = std::min(
*http_rtt,
*transport_rtt *
params_->upper_bound_http_rtt_transport_rtt_multiplier());
}
}
}
if (!GetRecentDownlinkThroughputKbps(start_time, downstream_throughput_kbps))
*downstream_throughput_kbps = nqe::internal::INVALID_RTT_THROUGHPUT;
if (*http_rtt == nqe::internal::InvalidRTT() &&
http_rtt_metric == NetworkQualityEstimator::MetricUsage::MUST_BE_USED) {
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
if (*transport_rtt == nqe::internal::InvalidRTT() &&
transport_rtt_metric ==
NetworkQualityEstimator::MetricUsage::MUST_BE_USED) {
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
if (*downstream_throughput_kbps == nqe::internal::INVALID_RTT_THROUGHPUT &&
downstream_throughput_kbps_metric ==
NetworkQualityEstimator::MetricUsage::MUST_BE_USED) {
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
if (*http_rtt == nqe::internal::InvalidRTT() &&
*transport_rtt == nqe::internal::InvalidRTT() &&
*downstream_throughput_kbps == nqe::internal::INVALID_RTT_THROUGHPUT) {
// None of the metrics are available.
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
// Search from the slowest connection type to the fastest to find the
// EffectiveConnectionType that best matches the current connection's
// performance. The match is done by comparing RTT and throughput.
for (size_t i = 0; i < EFFECTIVE_CONNECTION_TYPE_LAST; ++i) {
EffectiveConnectionType type = static_cast<EffectiveConnectionType>(i);
if (i == EFFECTIVE_CONNECTION_TYPE_UNKNOWN)
continue;
const bool estimated_http_rtt_is_higher_than_threshold =
http_rtt_metric != NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
*http_rtt != nqe::internal::InvalidRTT() &&
params_->ConnectionThreshold(type).http_rtt() !=
nqe::internal::InvalidRTT() &&
*http_rtt >= params_->ConnectionThreshold(type).http_rtt();
const bool estimated_transport_rtt_is_higher_than_threshold =
transport_rtt_metric !=
NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
*transport_rtt != nqe::internal::InvalidRTT() &&
params_->ConnectionThreshold(type).transport_rtt() !=
nqe::internal::InvalidRTT() &&
*transport_rtt >= params_->ConnectionThreshold(type).transport_rtt();
const bool estimated_throughput_is_lower_than_threshold =
downstream_throughput_kbps_metric !=
NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
*downstream_throughput_kbps != nqe::internal::INVALID_RTT_THROUGHPUT &&
params_->ConnectionThreshold(type).downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT &&
*downstream_throughput_kbps <=
params_->ConnectionThreshold(type).downstream_throughput_kbps();
if (estimated_http_rtt_is_higher_than_threshold ||
estimated_transport_rtt_is_higher_than_threshold ||
estimated_throughput_is_lower_than_threshold) {
return type;
}
}
// Return the fastest connection type.
return static_cast<EffectiveConnectionType>(EFFECTIVE_CONNECTION_TYPE_LAST -
1);
}
void NetworkQualityEstimator::AddEffectiveConnectionTypeObserver(
EffectiveConnectionTypeObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK(observer);
effective_connection_type_observer_list_.AddObserver(observer);
// Notify the |observer| on the next message pump since |observer| may not
// be completely set up for receiving the callbacks.
base::ThreadTaskRunnerHandle::Get()->PostTask(
FROM_HERE, base::Bind(&NetworkQualityEstimator::
NotifyEffectiveConnectionTypeObserverIfPresent,
weak_ptr_factory_.GetWeakPtr(), observer));
}
void NetworkQualityEstimator::RemoveEffectiveConnectionTypeObserver(
EffectiveConnectionTypeObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
effective_connection_type_observer_list_.RemoveObserver(observer);
}
void NetworkQualityEstimator::AddRTTAndThroughputEstimatesObserver(
RTTAndThroughputEstimatesObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK(observer);
rtt_and_throughput_estimates_observer_list_.AddObserver(observer);
// Notify the |observer| on the next message pump since |observer| may not
// be completely set up for receiving the callbacks.
base::ThreadTaskRunnerHandle::Get()->PostTask(
FROM_HERE,
base::Bind(&NetworkQualityEstimator::
NotifyRTTAndThroughputEstimatesObserverIfPresent,
weak_ptr_factory_.GetWeakPtr(), observer));
}
void NetworkQualityEstimator::RemoveRTTAndThroughputEstimatesObserver(
RTTAndThroughputEstimatesObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
rtt_and_throughput_estimates_observer_list_.RemoveObserver(observer);
}
bool NetworkQualityEstimator::GetRecentHttpRTT(
const base::TimeTicks& start_time,
base::TimeDelta* rtt) const {
DCHECK(thread_checker_.CalledOnValidThread());
*rtt = GetRTTEstimateInternal(start_time, base::Optional<Statistic>(),
nqe::internal::ObservationCategory::kHttp, 50,
nullptr);
return (*rtt != nqe::internal::InvalidRTT());
}
bool NetworkQualityEstimator::GetRecentTransportRTT(
const base::TimeTicks& start_time,
base::TimeDelta* rtt,
size_t* observations_count) const {
DCHECK(thread_checker_.CalledOnValidThread());
*rtt = GetRTTEstimateInternal(start_time, base::Optional<Statistic>(),
nqe::internal::ObservationCategory::kTransport,
50, observations_count);
return (*rtt != nqe::internal::InvalidRTT());
}
bool NetworkQualityEstimator::GetRecentDownlinkThroughputKbps(
const base::TimeTicks& start_time,
int32_t* kbps) const {
DCHECK(thread_checker_.CalledOnValidThread());
*kbps = GetDownlinkThroughputKbpsEstimateInternal(start_time, 50);
return (*kbps != nqe::internal::INVALID_RTT_THROUGHPUT);
}
base::TimeDelta NetworkQualityEstimator::GetRTTEstimateInternal(
base::TimeTicks start_time,
const base::Optional<Statistic>& statistic,
nqe::internal::ObservationCategory observation_category,
int percentile,
size_t* observations_count) const {
DCHECK(thread_checker_.CalledOnValidThread());
// RTT observations are sorted by duration from shortest to longest, thus
// a higher percentile RTT will have a longer RTT than a lower percentile.
if (!statistic) {
// Use default statistic algorithm.
switch (observation_category) {
case nqe::internal::ObservationCategory::kHttp:
return base::TimeDelta::FromMilliseconds(
http_rtt_ms_observations_
.GetPercentile(start_time, signal_strength_, percentile,
observations_count)
.value_or(nqe::internal::INVALID_RTT_THROUGHPUT));
case nqe::internal::ObservationCategory::kTransport:
return base::TimeDelta::FromMilliseconds(
transport_rtt_ms_observations_
.GetPercentile(start_time, signal_strength_, percentile,
observations_count)
.value_or(nqe::internal::INVALID_RTT_THROUGHPUT));
}
}
base::Optional<int32_t> rtt_ms;
switch (statistic.value()) {
case STATISTIC_LAST:
NOTREACHED();
return nqe::internal::InvalidRTT();
}
return base::TimeDelta::FromMilliseconds(
rtt_ms.value_or(nqe::internal::INVALID_RTT_THROUGHPUT));
}
int32_t NetworkQualityEstimator::GetDownlinkThroughputKbpsEstimateInternal(
const base::TimeTicks& start_time,
int percentile) const {
DCHECK(thread_checker_.CalledOnValidThread());
// Throughput observations are sorted by kbps from slowest to fastest,
// thus a higher percentile throughput will be faster than a lower one.
return http_downstream_throughput_kbps_observations_
.GetPercentile(start_time, signal_strength_, 100 - percentile, nullptr)
.value_or(nqe::internal::INVALID_RTT_THROUGHPUT);
}
nqe::internal::NetworkID NetworkQualityEstimator::GetCurrentNetworkID() const {
DCHECK(thread_checker_.CalledOnValidThread());
// TODO(tbansal): crbug.com/498068 Add NetworkQualityEstimatorAndroid class
// that overrides this method on the Android platform.
// It is possible that the connection type changed between when
// GetConnectionType() was called and when the API to determine the
// network name was called. Check if that happened and retry until the
// connection type stabilizes. This is an imperfect solution but should
// capture majority of cases, and should not significantly affect estimates
// (that are approximate to begin with).
while (true) {
nqe::internal::NetworkID network_id(
NetworkChangeNotifier::GetConnectionType(), std::string());
switch (network_id.type) {
case NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN:
case NetworkChangeNotifier::ConnectionType::CONNECTION_NONE:
case NetworkChangeNotifier::ConnectionType::CONNECTION_BLUETOOTH:
case NetworkChangeNotifier::ConnectionType::CONNECTION_ETHERNET:
break;
case NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI:
#if defined(OS_ANDROID) || defined(OS_LINUX) || defined(OS_WIN)
network_id.id = GetWifiSSID();
#endif
break;
case NetworkChangeNotifier::ConnectionType::CONNECTION_2G:
case NetworkChangeNotifier::ConnectionType::CONNECTION_3G:
case NetworkChangeNotifier::ConnectionType::CONNECTION_4G:
#if defined(OS_ANDROID)
network_id.id = android::GetTelephonyNetworkOperator();
#endif
break;
default:
NOTREACHED() << "Unexpected connection type = " << network_id.type;
break;
}
if (network_id.type == NetworkChangeNotifier::GetConnectionType())
return network_id;
}
NOTREACHED();
}
bool NetworkQualityEstimator::ReadCachedNetworkQualityEstimate() {
DCHECK(thread_checker_.CalledOnValidThread());
if (!params_->persistent_cache_reading_enabled())
return false;
if (current_network_id_.type !=
NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI &&
current_network_id_.type !=
NetworkChangeNotifier::ConnectionType::CONNECTION_ETHERNET &&
!disable_offline_check_) {
return false;
}
nqe::internal::CachedNetworkQuality cached_network_quality;
const bool cached_estimate_available = network_quality_store_->GetById(
current_network_id_, &cached_network_quality);
if (network_quality_store_->EligibleForCaching(current_network_id_)) {
UMA_HISTOGRAM_BOOLEAN("NQE.CachedNetworkQualityAvailable",
cached_estimate_available);
}
if (!cached_estimate_available)
return false;
const base::TimeTicks now = tick_clock_->NowTicks();
if (cached_network_quality.network_quality().downstream_throughput_kbps() !=
nqe::internal::INVALID_RTT_THROUGHPUT) {
Observation througphput_observation(
cached_network_quality.network_quality().downstream_throughput_kbps(),
now, INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE);
AddAndNotifyObserversOfThroughput(througphput_observation);
}
if (cached_network_quality.network_quality().http_rtt() !=
nqe::internal::InvalidRTT()) {
Observation rtt_observation(
cached_network_quality.network_quality().http_rtt().InMilliseconds(),
now, INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE);
AddAndNotifyObserversOfRTT(rtt_observation);
}
if (cached_network_quality.network_quality().transport_rtt() !=
nqe::internal::InvalidRTT()) {
Observation rtt_observation(
cached_network_quality.network_quality()
.transport_rtt()
.InMilliseconds(),
now, INT32_MIN,
NETWORK_QUALITY_OBSERVATION_SOURCE_TRANSPORT_CACHED_ESTIMATE);
AddAndNotifyObserversOfRTT(rtt_observation);
}
ComputeEffectiveConnectionType();
return true;
}
void NetworkQualityEstimator::OnUpdatedEstimateAvailable(
const base::TimeDelta& rtt,
int32_t downstream_throughput_kbps) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK(external_estimate_provider_);
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_CALLBACK);
external_estimate_provider_quality_ = nqe::internal::NetworkQuality();
if (rtt > base::TimeDelta()) {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_RTT_AVAILABLE);
UMA_HISTOGRAM_TIMES("NQE.ExternalEstimateProvider.RTT", rtt);
Observation rtt_observation(
rtt.InMilliseconds(), tick_clock_->NowTicks(), signal_strength_,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_EXTERNAL_ESTIMATE);
external_estimate_provider_quality_.set_http_rtt(rtt);
AddAndNotifyObserversOfRTT(rtt_observation);
}
if (downstream_throughput_kbps > 0) {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_DOWNLINK_BANDWIDTH_AVAILABLE);
UMA_HISTOGRAM_COUNTS_1M("NQE.ExternalEstimateProvider.DownlinkBandwidth",
downstream_throughput_kbps);
Observation throughput_observation(
downstream_throughput_kbps, tick_clock_->NowTicks(), signal_strength_,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_EXTERNAL_ESTIMATE);
external_estimate_provider_quality_.set_downstream_throughput_kbps(
downstream_throughput_kbps);
AddAndNotifyObserversOfThroughput(throughput_observation);
}
}
void NetworkQualityEstimator::SetTickClockForTesting(
std::unique_ptr<base::TickClock> tick_clock) {
DCHECK(thread_checker_.CalledOnValidThread());
tick_clock_ = std::move(tick_clock);
http_rtt_ms_observations_.SetTickClockForTesting(tick_clock_.get());
transport_rtt_ms_observations_.SetTickClockForTesting(tick_clock_.get());
http_downstream_throughput_kbps_observations_.SetTickClockForTesting(
tick_clock_.get());
throughput_analyzer_->SetTickClockForTesting(tick_clock_.get());
watcher_factory_->SetTickClockForTesting(tick_clock_.get());
}
double NetworkQualityEstimator::RandDouble() const {
return base::RandDouble();
}
void NetworkQualityEstimator::OnUpdatedTransportRTTAvailable(
SocketPerformanceWatcherFactory::Protocol protocol,
const base::TimeDelta& rtt,
const base::Optional<nqe::internal::IPHash>& host) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::InvalidRTT(), rtt);
Observation observation(rtt.InMilliseconds(), tick_clock_->NowTicks(),
signal_strength_,
ProtocolSourceToObservationSource(protocol), host);
AddAndNotifyObserversOfRTT(observation);
// Post a task to compute and update the increase in RTT if not already
// posted.
if (!increase_in_transport_rtt_updater_posted_)
IncreaseInTransportRTTUpdater();
}
void NetworkQualityEstimator::AddAndNotifyObserversOfRTT(
const Observation& observation) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::InvalidRTT(),
base::TimeDelta::FromMilliseconds(observation.value()));
DCHECK_GT(NETWORK_QUALITY_OBSERVATION_SOURCE_MAX, observation.source());
if (!ShouldAddObservation(observation))
return;
MaybeUpdateCachedEstimateApplied(observation, &http_rtt_ms_observations_);
MaybeUpdateCachedEstimateApplied(observation,
&transport_rtt_ms_observations_);
++new_rtt_observations_since_last_ect_computation_;
switch (observation.GetObservationCategory()) {
case nqe::internal::ObservationCategory::kHttp:
http_rtt_ms_observations_.AddObservation(observation);
break;
case nqe::internal::ObservationCategory::kTransport:
transport_rtt_ms_observations_.AddObservation(observation);
break;
}
if (observation.source() == NETWORK_QUALITY_OBSERVATION_SOURCE_TCP ||
observation.source() == NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC) {
last_socket_watcher_rtt_notification_ = tick_clock_->NowTicks();
}
UMA_HISTOGRAM_ENUMERATION("NQE.RTT.ObservationSource", observation.source(),
NETWORK_QUALITY_OBSERVATION_SOURCE_MAX);
base::HistogramBase* raw_observation_histogram = base::Histogram::FactoryGet(
std::string("NQE.RTT.RawObservation.") +
nqe::internal::GetNameForObservationSource(observation.source()),
1, 10 * 1000, 50, base::HistogramBase::kUmaTargetedHistogramFlag);
if (raw_observation_histogram)
raw_observation_histogram->Add(observation.value());
// Maybe recompute the effective connection type since a new RTT observation
// is available.
MaybeComputeEffectiveConnectionType();
for (auto& observer : rtt_observer_list_) {
observer.OnRTTObservation(observation.value(), observation.timestamp(),
observation.source());
}
}
void NetworkQualityEstimator::AddAndNotifyObserversOfThroughput(
const Observation& observation) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::INVALID_RTT_THROUGHPUT, observation.value());
DCHECK_GT(NETWORK_QUALITY_OBSERVATION_SOURCE_MAX, observation.source());
DCHECK_EQ(nqe::internal::ObservationCategory::kHttp,
observation.GetObservationCategory());
if (!ShouldAddObservation(observation))
return;
MaybeUpdateCachedEstimateApplied(
observation, &http_downstream_throughput_kbps_observations_);
++new_throughput_observations_since_last_ect_computation_;
http_downstream_throughput_kbps_observations_.AddObservation(observation);
UMA_HISTOGRAM_ENUMERATION("NQE.Kbps.ObservationSource", observation.source(),
NETWORK_QUALITY_OBSERVATION_SOURCE_MAX);
base::HistogramBase* raw_observation_histogram = base::Histogram::FactoryGet(
std::string("NQE.Kbps.RawObservation.") +
nqe::internal::GetNameForObservationSource(observation.source()),
1, 10 * 1000, 50, base::HistogramBase::kUmaTargetedHistogramFlag);
if (raw_observation_histogram)
raw_observation_histogram->Add(observation.value());
// Maybe recompute the effective connection type since a new throughput
// observation is available.
MaybeComputeEffectiveConnectionType();
for (auto& observer : throughput_observer_list_) {
observer.OnThroughputObservation(
observation.value(), observation.timestamp(), observation.source());
}
}
void NetworkQualityEstimator::OnNewThroughputObservationAvailable(
int32_t downstream_kbps) {
DCHECK(thread_checker_.CalledOnValidThread());
if (downstream_kbps <= 0)
return;
DCHECK_NE(nqe::internal::INVALID_RTT_THROUGHPUT, downstream_kbps);
Observation throughput_observation(downstream_kbps, tick_clock_->NowTicks(),
signal_strength_,
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP);
AddAndNotifyObserversOfThroughput(throughput_observation);
}
void NetworkQualityEstimator::MaybeComputeEffectiveConnectionType() {
DCHECK(thread_checker_.CalledOnValidThread());
const base::TimeTicks now = tick_clock_->NowTicks();
// Recompute effective connection type only if
// |effective_connection_type_recomputation_interval_| has passed since it was
// last computed or a connection change event was observed since the last
// computation. Strict inequalities are used to ensure that effective
// connection type is recomputed on connection change events even if the clock
// has not updated.
if (now - last_effective_connection_type_computation_ <
effective_connection_type_recomputation_interval_ &&
last_connection_change_ < last_effective_connection_type_computation_ &&
// Recompute the effective connection type if the previously computed
// effective connection type was unknown.
effective_connection_type_ != EFFECTIVE_CONNECTION_TYPE_UNKNOWN &&
// Recompute the effective connection type if the number of samples
// available now are 50% more than the number of samples that were
// available when the effective connection type was last computed.
rtt_observations_size_at_last_ect_computation_ * 1.5 >=
(http_rtt_ms_observations_.Size() +
transport_rtt_ms_observations_.Size()) &&
throughput_observations_size_at_last_ect_computation_ * 1.5 >=
http_downstream_throughput_kbps_observations_.Size() &&
(new_rtt_observations_since_last_ect_computation_ +
new_throughput_observations_since_last_ect_computation_) <
params_->count_new_observations_received_compute_ect()) {
return;
}
ComputeEffectiveConnectionType();
}
void NetworkQualityEstimator::
NotifyObserversOfEffectiveConnectionTypeChanged() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(EFFECTIVE_CONNECTION_TYPE_LAST, effective_connection_type_);
// TODO(tbansal): Add hysteresis in the notification.
for (auto& observer : effective_connection_type_observer_list_)
observer.OnEffectiveConnectionTypeChanged(effective_connection_type_);
// Add the estimates of the current network to the cache store.
network_quality_store_->Add(current_network_id_,
nqe::internal::CachedNetworkQuality(
tick_clock_->NowTicks(), network_quality_,
effective_connection_type_));
}
void NetworkQualityEstimator::NotifyObserversOfRTTOrThroughputComputed() const {
DCHECK(thread_checker_.CalledOnValidThread());
// TODO(tbansal): Add hysteresis in the notification.
for (auto& observer : rtt_and_throughput_estimates_observer_list_) {
observer.OnRTTOrThroughputEstimatesComputed(
network_quality_.http_rtt(), network_quality_.transport_rtt(),
network_quality_.downstream_throughput_kbps());
}
}
void NetworkQualityEstimator::NotifyEffectiveConnectionTypeObserverIfPresent(
EffectiveConnectionTypeObserver* observer) const {
DCHECK(thread_checker_.CalledOnValidThread());
if (!effective_connection_type_observer_list_.HasObserver(observer))
return;
if (effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_UNKNOWN)
return;
observer->OnEffectiveConnectionTypeChanged(effective_connection_type_);
}
void NetworkQualityEstimator::NotifyRTTAndThroughputEstimatesObserverIfPresent(
RTTAndThroughputEstimatesObserver* observer) const {
DCHECK(thread_checker_.CalledOnValidThread());
if (!rtt_and_throughput_estimates_observer_list_.HasObserver(observer))
return;
observer->OnRTTOrThroughputEstimatesComputed(
network_quality_.http_rtt(), network_quality_.transport_rtt(),
network_quality_.downstream_throughput_kbps());
}
void NetworkQualityEstimator::AddNetworkQualitiesCacheObserver(
nqe::internal::NetworkQualityStore::NetworkQualitiesCacheObserver*
observer) {
DCHECK(thread_checker_.CalledOnValidThread());
network_quality_store_->AddNetworkQualitiesCacheObserver(observer);
}
void NetworkQualityEstimator::RemoveNetworkQualitiesCacheObserver(
nqe::internal::NetworkQualityStore::NetworkQualitiesCacheObserver*
observer) {
DCHECK(thread_checker_.CalledOnValidThread());
network_quality_store_->RemoveNetworkQualitiesCacheObserver(observer);
}
void NetworkQualityEstimator::OnPrefsRead(
const std::map<nqe::internal::NetworkID,
nqe::internal::CachedNetworkQuality> read_prefs) {
DCHECK(thread_checker_.CalledOnValidThread());
UMA_HISTOGRAM_COUNTS_1M("NQE.Prefs.ReadSize", read_prefs.size());
for (auto& it : read_prefs) {
EffectiveConnectionType effective_connection_type =
it.second.effective_connection_type();
if (effective_connection_type == EFFECTIVE_CONNECTION_TYPE_UNKNOWN ||
effective_connection_type == EFFECTIVE_CONNECTION_TYPE_OFFLINE) {
continue;
}
// RTT and throughput values are not set in the prefs.
DCHECK_EQ(nqe::internal::InvalidRTT(),
it.second.network_quality().http_rtt());
DCHECK_EQ(nqe::internal::InvalidRTT(),
it.second.network_quality().transport_rtt());
DCHECK_EQ(nqe::internal::INVALID_RTT_THROUGHPUT,
it.second.network_quality().downstream_throughput_kbps());
nqe::internal::CachedNetworkQuality cached_network_quality(
tick_clock_->NowTicks(),
params_->TypicalNetworkQuality(effective_connection_type),
effective_connection_type);
network_quality_store_->Add(it.first, cached_network_quality);
}
ReadCachedNetworkQualityEstimate();
}
base::Optional<base::TimeDelta> NetworkQualityEstimator::GetHttpRTT() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (network_quality_.http_rtt() == nqe::internal::InvalidRTT())
return base::Optional<base::TimeDelta>();
return network_quality_.http_rtt();
}
base::Optional<base::TimeDelta> NetworkQualityEstimator::GetTransportRTT()
const {
DCHECK(thread_checker_.CalledOnValidThread());
if (network_quality_.transport_rtt() == nqe::internal::InvalidRTT())
return base::Optional<base::TimeDelta>();
return network_quality_.transport_rtt();
}
base::Optional<int32_t> NetworkQualityEstimator::GetDownstreamThroughputKbps()
const {
DCHECK(thread_checker_.CalledOnValidThread());
if (network_quality_.downstream_throughput_kbps() ==
nqe::internal::INVALID_RTT_THROUGHPUT) {
return base::Optional<int32_t>();
}
return network_quality_.downstream_throughput_kbps();
}
base::Optional<int32_t> NetworkQualityEstimator::GetBandwidthDelayProductKbits()
const {
DCHECK(thread_checker_.CalledOnValidThread());
return bandwidth_delay_product_kbits_;
}
const char* NetworkQualityEstimator::GetNameForStatistic(int i) const {
Statistic statistic = static_cast<Statistic>(i);
switch (statistic) {
case STATISTIC_LAST:
NOTREACHED();
return "";
}
NOTREACHED();
return "";
}
void NetworkQualityEstimator::MaybeUpdateCachedEstimateApplied(
const Observation& observation,
ObservationBuffer* buffer) {
DCHECK(thread_checker_.CalledOnValidThread());
if (observation.source() !=
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE &&
observation.source() !=
NETWORK_QUALITY_OBSERVATION_SOURCE_TRANSPORT_CACHED_ESTIMATE) {
return;
}
cached_estimate_applied_ = true;
bool deleted_observation_sources[NETWORK_QUALITY_OBSERVATION_SOURCE_MAX] = {
false};
deleted_observation_sources
[NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_EXTERNAL_ESTIMATE] = true;
deleted_observation_sources
[NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_HTTP_FROM_PLATFORM] = true;
deleted_observation_sources
[NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_TRANSPORT_FROM_PLATFORM] =
true;
buffer->RemoveObservationsWithSource(deleted_observation_sources);
}
bool NetworkQualityEstimator::ShouldAddObservation(
const Observation& observation) const {
DCHECK(thread_checker_.CalledOnValidThread());
if (cached_estimate_applied_ &&
(observation.source() ==
NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_EXTERNAL_ESTIMATE ||
observation.source() ==
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_HTTP_FROM_PLATFORM ||
observation.source() ==
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_TRANSPORT_FROM_PLATFORM)) {
return false;
}
return true;
}
bool NetworkQualityEstimator::ShouldSocketWatcherNotifyRTT(
base::TimeTicks now) {
DCHECK(thread_checker_.CalledOnValidThread());
return (now - last_socket_watcher_rtt_notification_ >=
params_->socket_watchers_min_notification_interval());
}
} // namespace net