blob: f98b4cda69ef7fa083574787970dcf0d9aa670da [file] [log] [blame]
// Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
//
#include "system_wrappers/include/metrics.h"
#include <algorithm>
#include "rtc_base/critical_section.h"
#include "rtc_base/thread_annotations.h"
// Default implementation of histogram methods for WebRTC clients that do not
// want to provide their own implementation.
namespace webrtc {
namespace metrics {
class Histogram;
namespace {
// Limit for the maximum number of sample values that can be stored.
// TODO(asapersson): Consider using bucket count (and set up
// linearly/exponentially spaced buckets) if samples are logged more frequently.
const int kMaxSampleMapSize = 300;
class RtcHistogram {
public:
RtcHistogram(const std::string& name, int min, int max, int bucket_count)
: min_(min), max_(max), info_(name, min, max, bucket_count) {
RTC_DCHECK_GT(bucket_count, 0);
}
void Add(int sample) {
sample = std::min(sample, max_);
sample = std::max(sample, min_ - 1); // Underflow bucket.
rtc::CritScope cs(&crit_);
if (info_.samples.size() == kMaxSampleMapSize &&
info_.samples.find(sample) == info_.samples.end()) {
return;
}
++info_.samples[sample];
}
// Returns a copy (or nullptr if there are no samples) and clears samples.
std::unique_ptr<SampleInfo> GetAndReset() {
rtc::CritScope cs(&crit_);
if (info_.samples.empty())
return nullptr;
SampleInfo* copy =
new SampleInfo(info_.name, info_.min, info_.max, info_.bucket_count);
std::swap(info_.samples, copy->samples);
return std::unique_ptr<SampleInfo>(copy);
}
const std::string& name() const { return info_.name; }
// Functions only for testing.
void Reset() {
rtc::CritScope cs(&crit_);
info_.samples.clear();
}
int NumEvents(int sample) const {
rtc::CritScope cs(&crit_);
const auto it = info_.samples.find(sample);
return (it == info_.samples.end()) ? 0 : it->second;
}
int NumSamples() const {
int num_samples = 0;
rtc::CritScope cs(&crit_);
for (const auto& sample : info_.samples) {
num_samples += sample.second;
}
return num_samples;
}
int MinSample() const {
rtc::CritScope cs(&crit_);
return (info_.samples.empty()) ? -1 : info_.samples.begin()->first;
}
private:
rtc::CriticalSection crit_;
const int min_;
const int max_;
SampleInfo info_ RTC_GUARDED_BY(crit_);
RTC_DISALLOW_COPY_AND_ASSIGN(RtcHistogram);
};
class RtcHistogramMap {
public:
RtcHistogramMap() {}
~RtcHistogramMap() {}
Histogram* GetCountsHistogram(const std::string& name,
int min,
int max,
int bucket_count) {
rtc::CritScope cs(&crit_);
const auto& it = map_.find(name);
if (it != map_.end())
return reinterpret_cast<Histogram*>(it->second.get());
RtcHistogram* hist = new RtcHistogram(name, min, max, bucket_count);
map_[name].reset(hist);
return reinterpret_cast<Histogram*>(hist);
}
Histogram* GetEnumerationHistogram(const std::string& name, int boundary) {
rtc::CritScope cs(&crit_);
const auto& it = map_.find(name);
if (it != map_.end())
return reinterpret_cast<Histogram*>(it->second.get());
RtcHistogram* hist = new RtcHistogram(name, 1, boundary, boundary + 1);
map_[name].reset(hist);
return reinterpret_cast<Histogram*>(hist);
}
void GetAndReset(
std::map<std::string, std::unique_ptr<SampleInfo>>* histograms) {
rtc::CritScope cs(&crit_);
for (const auto& kv : map_) {
std::unique_ptr<SampleInfo> info = kv.second->GetAndReset();
if (info)
histograms->insert(std::make_pair(kv.first, std::move(info)));
}
}
// Functions only for testing.
void Reset() {
rtc::CritScope cs(&crit_);
for (const auto& kv : map_)
kv.second->Reset();
}
int NumEvents(const std::string& name, int sample) const {
rtc::CritScope cs(&crit_);
const auto& it = map_.find(name);
return (it == map_.end()) ? 0 : it->second->NumEvents(sample);
}
int NumSamples(const std::string& name) const {
rtc::CritScope cs(&crit_);
const auto& it = map_.find(name);
return (it == map_.end()) ? 0 : it->second->NumSamples();
}
int MinSample(const std::string& name) const {
rtc::CritScope cs(&crit_);
const auto& it = map_.find(name);
return (it == map_.end()) ? -1 : it->second->MinSample();
}
private:
rtc::CriticalSection crit_;
std::map<std::string, std::unique_ptr<RtcHistogram>> map_
RTC_GUARDED_BY(crit_);
RTC_DISALLOW_COPY_AND_ASSIGN(RtcHistogramMap);
};
// RtcHistogramMap is allocated upon call to Enable().
// The histogram getter functions, which return pointer values to the histograms
// in the map, are cached in WebRTC. Therefore, this memory is not freed by the
// application (the memory will be reclaimed by the OS).
static RtcHistogramMap* volatile g_rtc_histogram_map = nullptr;
void CreateMap() {
RtcHistogramMap* map = rtc::AtomicOps::AcquireLoadPtr(&g_rtc_histogram_map);
if (map == nullptr) {
RtcHistogramMap* new_map = new RtcHistogramMap();
RtcHistogramMap* old_map = rtc::AtomicOps::CompareAndSwapPtr(
&g_rtc_histogram_map, static_cast<RtcHistogramMap*>(nullptr), new_map);
if (old_map != nullptr)
delete new_map;
}
}
// Set the first time we start using histograms. Used to make sure Enable() is
// not called thereafter.
#if RTC_DCHECK_IS_ON
static volatile int g_rtc_histogram_called = 0;
#endif
// Gets the map (or nullptr).
RtcHistogramMap* GetMap() {
#if RTC_DCHECK_IS_ON
rtc::AtomicOps::ReleaseStore(&g_rtc_histogram_called, 1);
#endif
return g_rtc_histogram_map;
}
} // namespace
#ifndef WEBRTC_EXCLUDE_METRICS_DEFAULT
// Implementation of histogram methods in
// webrtc/system_wrappers/interface/metrics.h.
// Histogram with exponentially spaced buckets.
// Creates (or finds) histogram.
// The returned histogram pointer is cached (and used for adding samples in
// subsequent calls).
Histogram* HistogramFactoryGetCounts(const std::string& name,
int min,
int max,
int bucket_count) {
// TODO(asapersson): Alternative implementation will be needed if this
// histogram type should be truly exponential.
return HistogramFactoryGetCountsLinear(name, min, max, bucket_count);
}
// Histogram with linearly spaced buckets.
// Creates (or finds) histogram.
// The returned histogram pointer is cached (and used for adding samples in
// subsequent calls).
Histogram* HistogramFactoryGetCountsLinear(const std::string& name,
int min,
int max,
int bucket_count) {
RtcHistogramMap* map = GetMap();
if (!map)
return nullptr;
return map->GetCountsHistogram(name, min, max, bucket_count);
}
// Histogram with linearly spaced buckets.
// Creates (or finds) histogram.
// The returned histogram pointer is cached (and used for adding samples in
// subsequent calls).
Histogram* HistogramFactoryGetEnumeration(const std::string& name,
int boundary) {
RtcHistogramMap* map = GetMap();
if (!map)
return nullptr;
return map->GetEnumerationHistogram(name, boundary);
}
// Our default implementation reuses the non-sparse histogram.
Histogram* SparseHistogramFactoryGetEnumeration(const std::string& name,
int boundary) {
return HistogramFactoryGetEnumeration(name, boundary);
}
// Fast path. Adds |sample| to cached |histogram_pointer|.
void HistogramAdd(Histogram* histogram_pointer, int sample) {
RtcHistogram* ptr = reinterpret_cast<RtcHistogram*>(histogram_pointer);
ptr->Add(sample);
}
#endif // WEBRTC_EXCLUDE_METRICS_DEFAULT
SampleInfo::SampleInfo(const std::string& name,
int min,
int max,
size_t bucket_count)
: name(name), min(min), max(max), bucket_count(bucket_count) {}
SampleInfo::~SampleInfo() {}
// Implementation of global functions in metrics.h.
void Enable() {
RTC_DCHECK(g_rtc_histogram_map == nullptr);
#if RTC_DCHECK_IS_ON
RTC_DCHECK_EQ(0, rtc::AtomicOps::AcquireLoad(&g_rtc_histogram_called));
#endif
CreateMap();
}
void GetAndReset(
std::map<std::string, std::unique_ptr<SampleInfo>>* histograms) {
histograms->clear();
RtcHistogramMap* map = GetMap();
if (map)
map->GetAndReset(histograms);
}
void Reset() {
RtcHistogramMap* map = GetMap();
if (map)
map->Reset();
}
int NumEvents(const std::string& name, int sample) {
RtcHistogramMap* map = GetMap();
return map ? map->NumEvents(name, sample) : 0;
}
int NumSamples(const std::string& name) {
RtcHistogramMap* map = GetMap();
return map ? map->NumSamples(name) : 0;
}
int MinSample(const std::string& name) {
RtcHistogramMap* map = GetMap();
return map ? map->MinSample(name) : -1;
}
} // namespace metrics
} // namespace webrtc