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chromium / chromium / src.git / 0de7df17b0f15613b30a422226d96c6429255d5c / . / net / nqe / network_quality_estimator.cc
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// 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 <vector>
#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/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/load_flags.h"
#include "net/base/load_timing_info.h"
#include "net/base/network_interfaces.h"
#include "net/base/url_util.h"
#include "net/http/http_status_code.h"
#include "net/nqe/socket_watcher_factory.h"
#include "net/nqe/throughput_analyzer.h"
#include "net/url_request/url_request.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 {
// Default value of the half life (in seconds) for computing time weighted
// percentiles. Every half life, the weight of all observations reduces by
// half. Lowering the half life would reduce the weight of older values faster.
const int kDefaultHalfLifeSeconds = 60;
// Name of the variation parameter that holds the value of the half life (in
// seconds) of the observations.
const char kHalfLifeSecondsParamName[] = "HalfLifeSeconds";
// Returns a descriptive name corresponding to |connection_type|.
const char* GetNameForConnectionType(
net::NetworkChangeNotifier::ConnectionType connection_type) {
switch (connection_type) {
case net::NetworkChangeNotifier::CONNECTION_UNKNOWN:
return "Unknown";
case net::NetworkChangeNotifier::CONNECTION_ETHERNET:
return "Ethernet";
case net::NetworkChangeNotifier::CONNECTION_WIFI:
return "WiFi";
case net::NetworkChangeNotifier::CONNECTION_2G:
return "2G";
case net::NetworkChangeNotifier::CONNECTION_3G:
return "3G";
case net::NetworkChangeNotifier::CONNECTION_4G:
return "4G";
case net::NetworkChangeNotifier::CONNECTION_NONE:
return "None";
case net::NetworkChangeNotifier::CONNECTION_BLUETOOTH:
return "Bluetooth";
default:
NOTREACHED();
break;
}
return "";
}
// Suffix of the name of the variation parameter that contains the default RTT
// observation (in milliseconds). Complete name of the variation parameter
// would be |ConnectionType|.|kDefaultRTTMsecObservationSuffix| where
// |ConnectionType| is from |kConnectionTypeNames|. For example, variation
// parameter for Wi-Fi would be "WiFi.DefaultMedianRTTMsec".
const char kDefaultRTTMsecObservationSuffix[] = ".DefaultMedianRTTMsec";
// Suffix of the name of the variation parameter that contains the default
// downstream throughput observation (in Kbps). Complete name of the variation
// parameter would be |ConnectionType|.|kDefaultKbpsObservationSuffix| where
// |ConnectionType| is from |kConnectionTypeNames|. For example, variation
// parameter for Wi-Fi would be "WiFi.DefaultMedianKbps".
const char kDefaultKbpsObservationSuffix[] = ".DefaultMedianKbps";
// Suffix of the name of the variation parameter that contains the threshold
// HTTP RTTs (in milliseconds) for different effective connection types.
// Complete name of the variation parameter would be
// |EffectiveConnectionType|.|kThresholdURLRTTMsecSuffix|.
const char kThresholdURLRTTMsecSuffix[] = ".ThresholdMedianHttpRTTMsec";
// Suffix of the name of the variation parameter that contains the threshold
// transport RTTs (in milliseconds) for different effective connection types.
// Complete name of the variation parameter would be
// |EffectiveConnectionType|.|kThresholdTransportRTTMsecSuffix|.
const char kThresholdTransportRTTMsecSuffix[] =
".ThresholdMedianTransportRTTMsec";
// Suffix of the name of the variation parameter that contains the threshold
// downlink throughput (in kbps) for different effective connection types.
// Complete name of the variation parameter would be
// |EffectiveConnectionType|.|kThresholdKbpsSuffix|.
const char kThresholdKbpsSuffix[] = ".ThresholdMedianKbps";
// Computes and returns the weight multiplier per second.
// |variation_params| is the map containing all field trial parameters
// related to NetworkQualityEstimator field trial.
double GetWeightMultiplierPerSecond(
const std::map<std::string, std::string>& variation_params) {
int half_life_seconds = kDefaultHalfLifeSeconds;
int32_t variations_value = 0;
auto it = variation_params.find(kHalfLifeSecondsParamName);
if (it != variation_params.end() &&
base::StringToInt(it->second, &variations_value) &&
variations_value >= 1) {
half_life_seconds = variations_value;
}
DCHECK_GT(half_life_seconds, 0);
return exp(log(0.5) / half_life_seconds);
}
// 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,
net::NetworkChangeNotifier::ConnectionType type,
int32_t max_limit) {
const base::LinearHistogram::Sample kLowerLimit = 1;
DCHECK_GT(max_limit, kLowerLimit);
const size_t kBucketCount = 50;
// Prefix of network quality estimator histograms.
const char prefix[] = "NQE.";
return base::Histogram::FactoryGet(
prefix + statistic_name + GetNameForConnectionType(type), kLowerLimit,
max_limit, kBucketCount, base::HistogramBase::kUmaTargetedHistogramFlag);
}
// Sets |variations_value| to the value of |parameter_name| read from
// |variation_params|. If the value is unavailable from |variation_params|, then
// |variations_value| is set to |default_value|.
void GetValueForVariationParam(
const std::map<std::string, std::string>& variation_params,
const std::string& parameter_name,
int64_t default_value,
int64_t* variations_value) {
const auto it = variation_params.find(parameter_name);
if (it != variation_params.end() &&
base::StringToInt64(it->second, variations_value)) {
return;
}
*variations_value = default_value;
}
// Returns the variation value for |parameter_name|. If the value is
// unavailable, |default_value| is returned.
double GetDoubleValueForVariationParamWithDefaultValue(
const std::map<std::string, std::string>& variation_params,
const std::string& parameter_name,
double default_value) {
const auto it = variation_params.find(parameter_name);
if (it == variation_params.end())
return default_value;
double variations_value = default_value;
if (!base::StringToDouble(it->second, &variations_value))
return default_value;
return variations_value;
}
// Returns the variation value for |parameter_name|. If the value is
// unavailable, |default_value| is returned.
std::string GetStringValueForVariationParamWithDefaultValue(
const std::map<std::string, std::string>& variation_params,
const std::string& parameter_name,
const std::string& default_value) {
const auto it = variation_params.find(parameter_name);
if (it == variation_params.end())
return default_value;
return it->second;
}
// Returns the algorithm that should be used for computing effective connection
// type based on field trial params. Returns an empty string if a valid
// algorithm paramter is not present in the field trial params.
std::string GetEffectiveConnectionTypeAlgorithm(
const std::map<std::string, std::string>& variation_params) {
const auto it = variation_params.find("effective_connection_type_algorithm");
if (it == variation_params.end())
return std::string();
return it->second;
}
net::NetworkQualityObservationSource ProtocolSourceToObservationSource(
net::SocketPerformanceWatcherFactory::Protocol protocol) {
switch (protocol) {
case net::SocketPerformanceWatcherFactory::PROTOCOL_TCP:
return net::NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
case net::SocketPerformanceWatcherFactory::PROTOCOL_QUIC:
return net::NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC;
}
NOTREACHED();
return net::NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
}
// Returns true if the scheme of the |request| is either HTTP or HTTPS.
bool RequestSchemeIsHTTPOrHTTPS(const net::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 float rtt_milliseconds = observed_rtt.InMillisecondsF();
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 <= static_cast<float>((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 <= static_cast<float>((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.
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);
return metric;
}
void RecordRTTAccuracy(const char* 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,
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,
net::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()),
net::GetNameForEffectiveConnectionType(
observed_effective_connection_type));
base::HistogramBase* histogram = base::Histogram::FactoryGet(
histogram_name, 0, net::EFFECTIVE_CONNECTION_TYPE_LAST,
net::EFFECTIVE_CONNECTION_TYPE_LAST /* Number of buckets */,
base::HistogramBase::kUmaTargetedHistogramFlag);
histogram->Add(std::abs(metric));
}
} // namespace
namespace net {
NetworkQualityEstimator::NetworkQualityEstimator(
std::unique_ptr<ExternalEstimateProvider> external_estimates_provider,
const std::map<std::string, std::string>& variation_params)
: NetworkQualityEstimator(std::move(external_estimates_provider),
variation_params,
false,
false) {}
NetworkQualityEstimator::NetworkQualityEstimator(
std::unique_ptr<ExternalEstimateProvider> external_estimates_provider,
const std::map<std::string, std::string>& variation_params,
bool use_local_host_requests_for_tests,
bool use_smaller_responses_for_tests)
: algorithm_name_to_enum_({{"HttpRTTAndDownstreamThroughput",
EffectiveConnectionTypeAlgorithm::
HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT},
{"TransportRTTOrDownstreamThroughput",
EffectiveConnectionTypeAlgorithm::
TRANSPORT_RTT_OR_DOWNSTREAM_THROUGHOUT}}),
use_localhost_requests_(use_local_host_requests_for_tests),
use_small_responses_(use_smaller_responses_for_tests),
weight_multiplier_per_second_(
GetWeightMultiplierPerSecond(variation_params)),
effective_connection_type_algorithm_(
algorithm_name_to_enum_.find(GetEffectiveConnectionTypeAlgorithm(
variation_params)) == algorithm_name_to_enum_.end()
? kDefaultEffectiveConnectionTypeAlgorithm
: algorithm_name_to_enum_
.find(GetEffectiveConnectionTypeAlgorithm(variation_params))
->second),
tick_clock_(new base::DefaultTickClock()),
last_connection_change_(tick_clock_->NowTicks()),
current_network_id_(nqe::internal::NetworkID(
NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN,
std::string())),
downstream_throughput_kbps_observations_(weight_multiplier_per_second_),
rtt_observations_(weight_multiplier_per_second_),
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),
effective_connection_type_(EFFECTIVE_CONNECTION_TYPE_UNKNOWN),
min_signal_strength_since_connection_change_(INT32_MAX),
max_signal_strength_since_connection_change_(INT32_MIN),
correlation_uma_logging_probability_(
GetDoubleValueForVariationParamWithDefaultValue(
variation_params,
"correlation_logging_probability",
0.0)),
forced_effective_connection_type_set_(
!GetStringValueForVariationParamWithDefaultValue(
variation_params,
"force_effective_connection_type",
"")
.empty()),
weak_ptr_factory_(this) {
static_assert(kDefaultHalfLifeSeconds > 0,
"Default half life duration must be > 0");
// None of the algorithms can have an empty name.
DCHECK(algorithm_name_to_enum_.end() ==
algorithm_name_to_enum_.find(std::string()));
DCHECK_EQ(algorithm_name_to_enum_.size(),
static_cast<size_t>(EffectiveConnectionTypeAlgorithm::
EFFECTIVE_CONNECTION_TYPE_ALGORITHM_LAST));
DCHECK_NE(EffectiveConnectionTypeAlgorithm::
EFFECTIVE_CONNECTION_TYPE_ALGORITHM_LAST,
effective_connection_type_algorithm_);
DCHECK_LE(0.0, correlation_uma_logging_probability_);
DCHECK_GE(1.0, correlation_uma_logging_probability_);
network_quality_store_.reset(new nqe::internal::NetworkQualityStore());
ObtainOperatingParams(variation_params);
ObtainEffectiveConnectionTypeModelParams(variation_params);
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);
}
current_network_id_ = GetCurrentNetworkID();
AddDefaultEstimates();
throughput_analyzer_.reset(new nqe::internal::ThroughputAnalyzer(
base::ThreadTaskRunnerHandle::Get(),
base::Bind(&NetworkQualityEstimator::OnNewThroughputObservationAvailable,
base::Unretained(this)),
use_localhost_requests_, use_smaller_responses_for_tests));
watcher_factory_.reset(new nqe::internal::SocketWatcherFactory(
base::ThreadTaskRunnerHandle::Get(),
base::Bind(&NetworkQualityEstimator::OnUpdatedRTTAvailable,
base::Unretained(this))));
// Record accuracy at 3 different intervals. 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));
accuracy_recording_intervals_.push_back(base::TimeDelta::FromSeconds(30));
accuracy_recording_intervals_.push_back(base::TimeDelta::FromSeconds(60));
if (forced_effective_connection_type_set_) {
std::string forced_value = GetStringValueForVariationParamWithDefaultValue(
variation_params, "force_effective_connection_type",
GetNameForEffectiveConnectionType(EFFECTIVE_CONNECTION_TYPE_UNKNOWN));
DCHECK(!forced_value.empty());
bool effective_connection_type_available =
GetEffectiveConnectionTypeForName(forced_value,
&forced_effective_connection_type_);
DCHECK(effective_connection_type_available);
// Silence unused variable warning in release builds.
(void)effective_connection_type_available;
}
}
void NetworkQualityEstimator::ObtainOperatingParams(
const std::map<std::string, std::string>& variation_params) {
DCHECK(thread_checker_.CalledOnValidThread());
for (size_t i = 0; i <= NetworkChangeNotifier::CONNECTION_LAST; ++i) {
NetworkChangeNotifier::ConnectionType type =
static_cast<NetworkChangeNotifier::ConnectionType>(i);
DCHECK_EQ(nqe::internal::InvalidRTT(), default_observations_[i].http_rtt());
DCHECK_EQ(nqe::internal::InvalidRTT(),
default_observations_[i].transport_rtt());
DCHECK_EQ(nqe::internal::kInvalidThroughput,
default_observations_[i].downstream_throughput_kbps());
int32_t variations_value = kMinimumRTTVariationParameterMsec - 1;
// Name of the parameter that holds the RTT value for this connection type.
std::string rtt_parameter_name =
std::string(GetNameForConnectionType(type))
.append(kDefaultRTTMsecObservationSuffix);
auto it = variation_params.find(rtt_parameter_name);
if (it != variation_params.end() &&
base::StringToInt(it->second, &variations_value) &&
variations_value >= kMinimumRTTVariationParameterMsec) {
default_observations_[i] = nqe::internal::NetworkQuality(
base::TimeDelta::FromMilliseconds(variations_value),
default_observations_[i].transport_rtt(),
default_observations_[i].downstream_throughput_kbps());
}
variations_value = kMinimumThroughputVariationParameterKbps - 1;
// Name of the parameter that holds the Kbps value for this connection
// type.
std::string kbps_parameter_name =
std::string(GetNameForConnectionType(type))
.append(kDefaultKbpsObservationSuffix);
it = variation_params.find(kbps_parameter_name);
if (it != variation_params.end() &&
base::StringToInt(it->second, &variations_value) &&
variations_value >= kMinimumThroughputVariationParameterKbps) {
default_observations_[i] = nqe::internal::NetworkQuality(
default_observations_[i].http_rtt(),
default_observations_[i].transport_rtt(), variations_value);
}
}
}
void NetworkQualityEstimator::ObtainEffectiveConnectionTypeModelParams(
const std::map<std::string, std::string>& variation_params) {
DCHECK(thread_checker_.CalledOnValidThread());
default_effective_connection_type_thresholds_
[EFFECTIVE_CONNECTION_TYPE_SLOW_2G] = nqe::internal::NetworkQuality(
// Set to 2010 milliseconds, which corresponds to the 33rd percentile
// of 2G HTTP RTT observations on Android.
base::TimeDelta::FromMilliseconds(2010),
// Set to 1870 milliseconds, which corresponds to the 33rd percentile
// of 2G transport RTT observations on Android.
base::TimeDelta::FromMilliseconds(1870),
nqe::internal::kInvalidThroughput);
default_effective_connection_type_thresholds_[EFFECTIVE_CONNECTION_TYPE_2G] =
nqe::internal::NetworkQuality(
// Set to 1420 milliseconds, which corresponds to 50th percentile of
// 2G
// HTTP RTT observations on Android.
base::TimeDelta::FromMilliseconds(1420),
// Set to 1280 milliseconds, which corresponds to 50th percentile of
// 2G
// transport RTT observations on Android.
base::TimeDelta::FromMilliseconds(1280),
nqe::internal::kInvalidThroughput);
for (size_t i = 0; i < EFFECTIVE_CONNECTION_TYPE_LAST; ++i) {
EffectiveConnectionType effective_connection_type =
static_cast<EffectiveConnectionType>(i);
DCHECK_EQ(nqe::internal::InvalidRTT(),
connection_thresholds_[i].http_rtt());
DCHECK_EQ(nqe::internal::InvalidRTT(),
connection_thresholds_[i].transport_rtt());
DCHECK_EQ(nqe::internal::kInvalidThroughput,
connection_thresholds_[i].downstream_throughput_kbps());
if (effective_connection_type == EFFECTIVE_CONNECTION_TYPE_UNKNOWN)
continue;
std::string connection_type_name = std::string(
GetNameForEffectiveConnectionType(effective_connection_type));
int64_t variations_value;
GetValueForVariationParam(variation_params,
connection_type_name + kThresholdURLRTTMsecSuffix,
default_effective_connection_type_thresholds_[i]
.http_rtt()
.InMilliseconds(),
&variations_value);
connection_thresholds_[i].set_http_rtt(
base::TimeDelta::FromMilliseconds(variations_value));
GetValueForVariationParam(
variation_params,
connection_type_name + kThresholdTransportRTTMsecSuffix,
default_effective_connection_type_thresholds_[i]
.transport_rtt()
.InMilliseconds(),
&variations_value);
connection_thresholds_[i].set_transport_rtt(
base::TimeDelta::FromMilliseconds(variations_value));
GetValueForVariationParam(variation_params,
connection_type_name + kThresholdKbpsSuffix,
default_effective_connection_type_thresholds_[i]
.downstream_throughput_kbps(),
&variations_value);
connection_thresholds_[i].set_downstream_throughput_kbps(variations_value);
DCHECK(i == 0 ||
connection_thresholds_[i].IsFaster(connection_thresholds_[i - 1]));
}
}
void NetworkQualityEstimator::AddDefaultEstimates() {
DCHECK(thread_checker_.CalledOnValidThread());
if (default_observations_[current_network_id_.type].http_rtt() !=
nqe::internal::InvalidRTT()) {
RttObservation rtt_observation(
default_observations_[current_network_id_.type].http_rtt(),
tick_clock_->NowTicks(),
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_FROM_PLATFORM);
rtt_observations_.AddObservation(rtt_observation);
NotifyObserversOfRTT(rtt_observation);
}
if (default_observations_[current_network_id_.type]
.downstream_throughput_kbps() != nqe::internal::kInvalidThroughput) {
ThroughputObservation throughput_observation(
default_observations_[current_network_id_.type]
.downstream_throughput_kbps(),
tick_clock_->NowTicks(),
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_FROM_PLATFORM);
downstream_throughput_kbps_observations_.AddObservation(
throughput_observation);
NotifyObserversOfThroughput(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;
throughput_analyzer_->NotifyStartTransaction(request);
}
void NetworkQualityEstimator::NotifyHeadersReceived(const URLRequest& request) {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("net"),
"NetworkQualityEstimator::NotifyHeadersReceived");
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request) ||
!RequestProvidesRTTObservation(request)) {
return;
}
const base::TimeTicks now = tick_clock_->NowTicks();
// Update |estimated_quality_at_last_main_frame_| if this is a main frame
// request.
if (request.load_flags() & LOAD_MAIN_FRAME_DEPRECATED) {
last_main_frame_request_ = now;
base::TimeDelta estimated_http_rtt;
if (!GetHttpRTT(&estimated_http_rtt))
estimated_http_rtt = nqe::internal::InvalidRTT();
base::TimeDelta estimated_transport_rtt;
if (!GetTransportRTT(&estimated_transport_rtt))
estimated_transport_rtt = nqe::internal::InvalidRTT();
int32_t downstream_throughput_kbps;
if (!GetDownlinkThroughputKbps(&downstream_throughput_kbps))
downstream_throughput_kbps = nqe::internal::kInvalidThroughput;
estimated_quality_at_last_main_frame_ = nqe::internal::NetworkQuality(
estimated_http_rtt, estimated_transport_rtt,
downstream_throughput_kbps);
ComputeEffectiveConnectionType();
effective_connection_type_at_last_main_frame_ =
GetEffectiveConnectionType();
RecordMetricsOnMainFrameRequest();
MaybeQueryExternalEstimateProvider();
// 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);
}
UpdateSignalStrength();
}
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.
base::TimeDelta observed_http_rtt =
load_timing_info.receive_headers_end - load_timing_info.send_start;
DCHECK_GE(observed_http_rtt, base::TimeDelta());
if (observed_http_rtt < peak_network_quality_.http_rtt()) {
peak_network_quality_ = nqe::internal::NetworkQuality(
observed_http_rtt, peak_network_quality_.transport_rtt(),
peak_network_quality_.downstream_throughput_kbps());
}
RttObservation http_rtt_observation(
observed_http_rtt, now, NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST);
rtt_observations_.AddObservation(http_rtt_observation);
NotifyObserversOfRTT(http_rtt_observation);
}
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 (estimated_quality_at_last_main_frame_.http_rtt() !=
nqe::internal::InvalidRTT() &&
GetRecentHttpRTT(last_main_frame_request_, &recent_http_rtt)) {
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)) {
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::kInvalidThroughput &&
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) {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("net"),
"NetworkQualityEstimator::NotifyRequestCompleted");
DCHECK(thread_checker_.CalledOnValidThread());
if (!RequestSchemeIsHTTPOrHTTPS(request))
return;
throughput_analyzer_->NotifyRequestCompleted(request);
RecordCorrelationMetric(request);
}
void NetworkQualityEstimator::RecordCorrelationMetric(
const URLRequest& request) const {
DCHECK(thread_checker_.CalledOnValidThread());
// The histogram is recorded with probability
// |correlation_uma_logging_probability_| to reduce overhead involved with
// sparse histograms. Also, recording the correlation on each request is
// unnecessary.
if (RandDouble() >= 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 (!request.status().is_success() || request.status().is_io_pending())
return;
if (request.GetResponseCode() != HTTP_OK)
return;
if (load_timing_info.receive_headers_end < last_main_frame_request_)
return;
const base::TimeTicks now = tick_clock_->NowTicks();
// Record UMA only for requests that started recently.
if (now - last_main_frame_request_ > base::TimeDelta::FromSeconds(15))
return;
DCHECK_GE(now, load_timing_info.send_start);
int32_t rtt = 0;
if (UseTransportRTT()) {
rtt = estimated_quality_at_last_main_frame_.transport_rtt() !=
nqe::internal::InvalidRTT()
? FitInKBitsPerMetricBits(
estimated_quality_at_last_main_frame_.transport_rtt()
.InMilliseconds())
: 0;
} else {
rtt = estimated_quality_at_last_main_frame_.http_rtt() !=
nqe::internal::InvalidRTT()
? FitInKBitsPerMetricBits(
estimated_quality_at_last_main_frame_.http_rtt()
.InMilliseconds())
: 0;
}
const int32_t downstream_throughput =
estimated_quality_at_last_main_frame_.downstream_throughput_kbps() !=
nqe::internal::kInvalidThroughput
? FitInKBitsPerMetricBits(estimated_quality_at_last_main_frame_
.downstream_throughput_kbps())
: 0;
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;
throughput_analyzer_->SetUseLocalHostRequestsForTesting(
use_localhost_requests_);
}
void NetworkQualityEstimator::SetUseSmallResponsesForTesting(
bool use_small_responses) {
DCHECK(thread_checker_.CalledOnValidThread());
use_small_responses_ = use_small_responses;
throughput_analyzer_->SetUseSmallResponsesForTesting(use_small_responses_);
}
void NetworkQualityEstimator::ReportEffectiveConnectionTypeForTesting(
EffectiveConnectionType effective_connection_type) {
DCHECK(thread_checker_.CalledOnValidThread());
FOR_EACH_OBSERVER(
EffectiveConnectionTypeObserver, effective_connection_type_observer_list_,
OnEffectiveConnectionTypeChanged(effective_connection_type));
}
bool NetworkQualityEstimator::RequestProvidesRTTObservation(
const URLRequest& request) const {
DCHECK(thread_checker_.CalledOnValidThread());
return (use_localhost_requests_ || !IsLocalhost(request.url().host())) &&
// 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_;
}
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_,
estimated_quality_at_last_main_frame_, effective_connection_type_));
// Clear the local state.
last_connection_change_ = tick_clock_->NowTicks();
peak_network_quality_ = nqe::internal::NetworkQuality();
downstream_throughput_kbps_observations_.Clear();
rtt_observations_.Clear();
#if defined(OS_ANDROID)
if (NetworkChangeNotifier::IsConnectionCellular(current_network_id_.type)) {
UMA_HISTOGRAM_BOOLEAN(
"NQE.CellularSignalStrengthAvailable",
min_signal_strength_since_connection_change_ != INT32_MAX &&
max_signal_strength_since_connection_change_ != INT32_MIN);
}
#endif // OS_ANDROID
min_signal_strength_since_connection_change_ = INT32_MAX;
max_signal_strength_since_connection_change_ = INT32_MIN;
estimated_quality_at_last_main_frame_ = nqe::internal::NetworkQuality();
effective_connection_type_ = EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
effective_connection_type_at_last_main_frame_ =
EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
// 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();
estimated_quality_at_last_main_frame_ = nqe::internal::NetworkQuality();
throughput_analyzer_->OnConnectionTypeChanged();
MaybeComputeEffectiveConnectionType();
UpdateSignalStrength();
}
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) {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERIED);
external_estimate_provider_->Update();
}
}
void NetworkQualityEstimator::UpdateSignalStrength() {
#if defined(OS_ANDROID)
int32_t signal_strength_dbm;
if (!android::cellular_signal_strength::GetSignalStrengthDbm(
&signal_strength_dbm)) {
return;
}
min_signal_strength_since_connection_change_ = std::min(
min_signal_strength_since_connection_change_, signal_strength_dbm);
max_signal_strength_since_connection_change_ = std::max(
max_signal_strength_since_connection_change_, signal_strength_dbm);
#endif // OS_ANDROID
}
void NetworkQualityEstimator::RecordMetricsOnConnectionTypeChanged() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (peak_network_quality_.http_rtt() != nqe::internal::InvalidRTT()) {
base::HistogramBase* rtt_histogram =
GetHistogram("FastestRTT.", current_network_id_.type, 10 * 1000);
rtt_histogram->Add(peak_network_quality_.http_rtt().InMilliseconds());
}
if (peak_network_quality_.downstream_throughput_kbps() !=
nqe::internal::kInvalidThroughput) {
base::HistogramBase* downstream_throughput_histogram =
GetHistogram("PeakKbps.", current_network_id_.type, 1000 * 1000);
downstream_throughput_histogram->Add(
peak_network_quality_.downstream_throughput_kbps());
}
base::TimeDelta rtt;
if (GetHttpRTT(&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};
std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_TCP);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC);
for (size_t i = 0; i < arraysize(kPercentiles); ++i) {
rtt = GetRTTEstimateInternal(disallowed_observation_sources,
base::TimeTicks(), kPercentiles[i]);
rtt_percentile = GetHistogram(
"RTT.Percentile" + base::IntToString(kPercentiles[i]) + ".",
current_network_id_.type, 10 * 1000); // 10 seconds
rtt_percentile->Add(rtt.InMilliseconds());
}
}
if (GetTransportRTT(&rtt)) {
// 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};
std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST);
// Disallow external estimate provider since it provides RTT at HTTP layer.
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_EXTERNAL_ESTIMATE);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_CACHED_ESTIMATE);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_FROM_PLATFORM);
for (size_t i = 0; i < arraysize(kPercentiles); ++i) {
rtt = GetRTTEstimateInternal(disallowed_observation_sources,
base::TimeTicks(), kPercentiles[i]);
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());
base::TimeDelta http_rtt;
if (GetHttpRTT(&http_rtt)) {
// Add the 50th percentile value.
base::HistogramBase* rtt_percentile = GetHistogram(
"MainFrame.RTT.Percentile50.", current_network_id_.type, 10 * 1000);
rtt_percentile->Add(http_rtt.InMilliseconds());
}
base::TimeDelta transport_rtt;
if (GetTransportRTT(&transport_rtt)) {
// Add the 50th percentile value.
base::HistogramBase* transport_rtt_percentile =
GetHistogram("MainFrame.TransportRTT.Percentile50.",
current_network_id_.type, 10 * 1000);
transport_rtt_percentile->Add(transport_rtt.InMilliseconds());
}
int32_t kbps;
if (GetDownlinkThroughputKbps(&kbps)) {
// Add the 50th percentile value.
base::HistogramBase* throughput_percentile = GetHistogram(
"MainFrame.Kbps.Percentile50.", current_network_id_.type, 1000 * 1000);
throughput_percentile->Add(kbps);
}
const EffectiveConnectionType effective_connection_type =
GetEffectiveConnectionType();
base::HistogramBase* effective_connection_type_histogram =
base::Histogram::FactoryGet(
std::string("NQE.MainFrame.EffectiveConnectionType.") +
GetNameForConnectionType(current_network_id_.type),
0, EFFECTIVE_CONNECTION_TYPE_LAST,
EFFECTIVE_CONNECTION_TYPE_LAST /* Number of buckets */,
base::HistogramBase::kUmaTargetedHistogramFlag);
effective_connection_type_histogram->Add(effective_connection_type);
}
void NetworkQualityEstimator::ComputeEffectiveConnectionType() {
DCHECK(thread_checker_.CalledOnValidThread());
const base::TimeTicks now = tick_clock_->NowTicks();
const EffectiveConnectionType past_type = effective_connection_type_;
last_effective_connection_type_computation_ = now;
effective_connection_type_ =
GetRecentEffectiveConnectionType(base::TimeTicks());
if (past_type != effective_connection_type_)
NotifyObserversOfEffectiveConnectionTypeChanged();
rtt_observations_size_at_last_ect_computation_ = rtt_observations_.Size();
throughput_observations_size_at_last_ect_computation_ =
downstream_throughput_kbps_observations_.Size();
}
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());
if (effective_connection_type_algorithm_ ==
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::
MUST_BE_USED /* downstream_throughput_kbps_metric */);
}
if (effective_connection_type_algorithm_ ==
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 */);
}
// Add additional algorithms here.
NOTREACHED();
return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
}
bool NetworkQualityEstimator::UseTransportRTT() const {
DCHECK(thread_checker_.CalledOnValidThread());
if (effective_connection_type_algorithm_ ==
EffectiveConnectionTypeAlgorithm::HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT) {
return false;
}
if (effective_connection_type_algorithm_ ==
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)
const {
DCHECK(thread_checker_.CalledOnValidThread());
if (forced_effective_connection_type_set_)
return forced_effective_connection_type_;
// If the device is currently offline, then return
// EFFECTIVE_CONNECTION_TYPE_OFFLINE.
if (current_network_id_.type == NetworkChangeNotifier::CONNECTION_NONE)
return EFFECTIVE_CONNECTION_TYPE_OFFLINE;
base::TimeDelta http_rtt = nqe::internal::InvalidRTT();
if (http_rtt_metric != NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
!GetRecentHttpRTT(start_time, &http_rtt)) {
http_rtt = nqe::internal::InvalidRTT();
}
base::TimeDelta transport_rtt = nqe::internal::InvalidRTT();
if (transport_rtt_metric !=
NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
!GetRecentTransportRTT(start_time, &transport_rtt)) {
transport_rtt = nqe::internal::InvalidRTT();
}
int32_t kbps = nqe::internal::kInvalidThroughput;
if (downstream_throughput_kbps_metric !=
NetworkQualityEstimator::MetricUsage::DO_NOT_USE &&
!GetRecentDownlinkThroughputKbps(start_time, &kbps)) {
kbps = nqe::internal::kInvalidThroughput;
}
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 (kbps == nqe::internal::kInvalidThroughput &&
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() &&
kbps == nqe::internal::kInvalidThroughput) {
// 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 != nqe::internal::InvalidRTT() &&
connection_thresholds_[i].http_rtt() != nqe::internal::InvalidRTT() &&
http_rtt >= connection_thresholds_[i].http_rtt();
const bool estimated_transport_rtt_is_higher_than_threshold =
transport_rtt != nqe::internal::InvalidRTT() &&
connection_thresholds_[i].transport_rtt() !=
nqe::internal::InvalidRTT() &&
transport_rtt >= connection_thresholds_[i].transport_rtt();
const bool estimated_throughput_is_lower_than_threshold =
kbps != nqe::internal::kInvalidThroughput &&
connection_thresholds_[i].downstream_throughput_kbps() !=
nqe::internal::kInvalidThroughput &&
kbps <= connection_thresholds_[i].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);
}
nqe::internal::NetworkQualityStore*
NetworkQualityEstimator::NetworkQualityStoreForTesting() const {
DCHECK(thread_checker_.CalledOnValidThread());
return network_quality_store_.get();
}
void NetworkQualityEstimator::AddEffectiveConnectionTypeObserver(
EffectiveConnectionTypeObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
effective_connection_type_observer_list_.AddObserver(observer);
}
void NetworkQualityEstimator::RemoveEffectiveConnectionTypeObserver(
EffectiveConnectionTypeObserver* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
effective_connection_type_observer_list_.RemoveObserver(observer);
}
bool NetworkQualityEstimator::GetHttpRTT(base::TimeDelta* rtt) const {
DCHECK(thread_checker_.CalledOnValidThread());
return GetRecentHttpRTT(base::TimeTicks(), rtt);
}
bool NetworkQualityEstimator::GetTransportRTT(base::TimeDelta* rtt) const {
DCHECK(thread_checker_.CalledOnValidThread());
return GetRecentTransportRTT(base::TimeTicks(), rtt);
}
bool NetworkQualityEstimator::GetDownlinkThroughputKbps(int32_t* kbps) const {
DCHECK(thread_checker_.CalledOnValidThread());
return GetRecentDownlinkThroughputKbps(base::TimeTicks(), kbps);
}
bool NetworkQualityEstimator::GetRecentHttpRTT(
const base::TimeTicks& start_time,
base::TimeDelta* rtt) const {
DCHECK(thread_checker_.CalledOnValidThread());
std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_TCP);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC);
*rtt = GetRTTEstimateInternal(disallowed_observation_sources, start_time, 50);
return (*rtt != nqe::internal::InvalidRTT());
}
bool NetworkQualityEstimator::GetRecentTransportRTT(
const base::TimeTicks& start_time,
base::TimeDelta* rtt) const {
DCHECK(thread_checker_.CalledOnValidThread());
std::vector<NetworkQualityObservationSource> disallowed_observation_sources;
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST);
// Disallow external estimate provider since it provides RTT at HTTP layer.
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_EXTERNAL_ESTIMATE);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_CACHED_ESTIMATE);
disallowed_observation_sources.push_back(
NETWORK_QUALITY_OBSERVATION_SOURCE_DEFAULT_FROM_PLATFORM);
*rtt = GetRTTEstimateInternal(disallowed_observation_sources, start_time, 50);
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::kInvalidThroughput);
}
base::TimeDelta NetworkQualityEstimator::GetRTTEstimateInternal(
const std::vector<NetworkQualityObservationSource>&
disallowed_observation_sources,
const base::TimeTicks& start_time,
int percentile) 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.
base::TimeDelta rtt = nqe::internal::InvalidRTT();
if (!rtt_observations_.GetPercentile(start_time, &rtt, percentile,
disallowed_observation_sources)) {
return nqe::internal::InvalidRTT();
}
return rtt;
}
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.
int32_t kbps = nqe::internal::kInvalidThroughput;
if (!downstream_throughput_kbps_observations_.GetPercentile(
start_time, &kbps, 100 - percentile,
std::vector<NetworkQualityObservationSource>())) {
return nqe::internal::kInvalidThroughput;
}
return kbps;
}
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_CHROMEOS) || \
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());
nqe::internal::CachedNetworkQuality cached_network_quality;
const bool cached_estimate_available = network_quality_store_->GetById(
current_network_id_, &cached_network_quality);
UMA_HISTOGRAM_BOOLEAN("NQE.CachedNetworkQualityAvailable",
cached_estimate_available);
if (!cached_estimate_available)
return false;
const base::TimeTicks now = tick_clock_->NowTicks();
if (effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_UNKNOWN) {
// Read the effective connection type from the cached estimate.
last_effective_connection_type_computation_ = now;
effective_connection_type_ =
cached_network_quality.effective_connection_type();
if (effective_connection_type_ != EFFECTIVE_CONNECTION_TYPE_UNKNOWN)
NotifyObserversOfEffectiveConnectionTypeChanged();
}
if (cached_network_quality.network_quality().downstream_throughput_kbps() !=
nqe::internal::kInvalidThroughput) {
ThroughputObservation througphput_observation(
cached_network_quality.network_quality().downstream_throughput_kbps(),
now, NETWORK_QUALITY_OBSERVATION_SOURCE_CACHED_ESTIMATE);
downstream_throughput_kbps_observations_.AddObservation(
througphput_observation);
NotifyObserversOfThroughput(througphput_observation);
}
if (cached_network_quality.network_quality().http_rtt() !=
nqe::internal::InvalidRTT()) {
RttObservation rtt_observation(
cached_network_quality.network_quality().http_rtt(), now,
NETWORK_QUALITY_OBSERVATION_SOURCE_CACHED_ESTIMATE);
rtt_observations_.AddObservation(rtt_observation);
NotifyObserversOfRTT(rtt_observation);
}
return true;
}
void NetworkQualityEstimator::OnUpdatedEstimateAvailable(
const base::TimeDelta& rtt,
int32_t downstream_throughput_kbps,
int32_t upstream_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);
rtt_observations_.AddObservation(
RttObservation(rtt, tick_clock_->NowTicks(),
NETWORK_QUALITY_OBSERVATION_SOURCE_EXTERNAL_ESTIMATE));
external_estimate_provider_quality_.set_http_rtt(rtt);
}
if (downstream_throughput_kbps > 0) {
RecordExternalEstimateProviderMetrics(
EXTERNAL_ESTIMATE_PROVIDER_STATUS_DOWNLINK_BANDWIDTH_AVAILABLE);
UMA_HISTOGRAM_COUNTS("NQE.ExternalEstimateProvider.DownlinkBandwidth",
downstream_throughput_kbps);
downstream_throughput_kbps_observations_.AddObservation(
ThroughputObservation(
downstream_throughput_kbps, tick_clock_->NowTicks(),
NETWORK_QUALITY_OBSERVATION_SOURCE_EXTERNAL_ESTIMATE));
external_estimate_provider_quality_.set_downstream_throughput_kbps(
downstream_throughput_kbps);
}
}
void NetworkQualityEstimator::SetTickClockForTesting(
std::unique_ptr<base::TickClock> tick_clock) {
DCHECK(thread_checker_.CalledOnValidThread());
tick_clock_ = std::move(tick_clock);
}
double NetworkQualityEstimator::RandDouble() const {
return base::RandDouble();
}
void NetworkQualityEstimator::OnUpdatedRTTAvailable(
SocketPerformanceWatcherFactory::Protocol protocol,
const base::TimeDelta& rtt) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::InvalidRTT(), rtt);
RttObservation observation(rtt, tick_clock_->NowTicks(),
ProtocolSourceToObservationSource(protocol));
NotifyObserversOfRTT(observation);
rtt_observations_.AddObservation(observation);
}
void NetworkQualityEstimator::NotifyObserversOfRTT(
const RttObservation& observation) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::InvalidRTT(), observation.value);
// Maybe recompute the effective connection type since a new RTT observation
// is available.
MaybeComputeEffectiveConnectionType();
FOR_EACH_OBSERVER(
RTTObserver, rtt_observer_list_,
OnRTTObservation(observation.value.InMilliseconds(),
observation.timestamp, observation.source));
}
void NetworkQualityEstimator::NotifyObserversOfThroughput(
const ThroughputObservation& observation) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(nqe::internal::kInvalidThroughput, observation.value);
// Maybe recompute the effective connection type since a new throughput
// observation is available.
MaybeComputeEffectiveConnectionType();
FOR_EACH_OBSERVER(
ThroughputObserver, throughput_observer_list_,
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::kInvalidThroughput, downstream_kbps);
if (downstream_kbps > peak_network_quality_.downstream_throughput_kbps()) {
peak_network_quality_ = nqe::internal::NetworkQuality(
peak_network_quality_.http_rtt(), peak_network_quality_.transport_rtt(),
downstream_kbps);
}
ThroughputObservation throughput_observation(
downstream_kbps, tick_clock_->NowTicks(),
NETWORK_QUALITY_OBSERVATION_SOURCE_URL_REQUEST);
downstream_throughput_kbps_observations_.AddObservation(
throughput_observation);
NotifyObserversOfThroughput(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 >=
rtt_observations_.Size() &&
throughput_observations_size_at_last_ect_computation_ * 1.5 >=
downstream_throughput_kbps_observations_.Size()) {
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_EACH_OBSERVER(
EffectiveConnectionTypeObserver, effective_connection_type_observer_list_,
OnEffectiveConnectionTypeChanged(effective_connection_type_));
// Add the estimates of the current network to the cache store.
if (effective_connection_type_ != EFFECTIVE_CONNECTION_TYPE_UNKNOWN) {
network_quality_store_->Add(
current_network_id_,
nqe::internal::CachedNetworkQuality(
tick_clock_->NowTicks(), estimated_quality_at_last_main_frame_,
effective_connection_type_));
}
}
} // namespace net