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- // Copyright (c) 2012 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 "base/metrics/sparse_histogram.h"
- #include <utility>
- #include "base/logging.h"
- #include "base/memory/ptr_util.h"
- #include "base/metrics/dummy_histogram.h"
- #include "base/metrics/metrics_hashes.h"
- #include "base/metrics/persistent_histogram_allocator.h"
- #include "base/metrics/persistent_sample_map.h"
- #include "base/metrics/sample_map.h"
- #include "base/metrics/statistics_recorder.h"
- #include "base/notreached.h"
- #include "base/pickle.h"
- #include "base/strings/utf_string_conversions.h"
- #include "base/synchronization/lock.h"
- #include "base/values.h"
- namespace base {
- typedef HistogramBase::Count Count;
- typedef HistogramBase::Sample Sample;
- // static
- HistogramBase* SparseHistogram::FactoryGet(const std::string& name,
- int32_t flags) {
- HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
- if (!histogram) {
- // TODO(gayane): |HashMetricName| is called again in Histogram constructor.
- // Refactor code to avoid the additional call.
- bool should_record =
- StatisticsRecorder::ShouldRecordHistogram(HashMetricNameAs32Bits(name));
- if (!should_record)
- return DummyHistogram::GetInstance();
- // Try to create the histogram using a "persistent" allocator. As of
- // 2016-02-25, the availability of such is controlled by a base::Feature
- // that is off by default. If the allocator doesn't exist or if
- // allocating from it fails, code below will allocate the histogram from
- // the process heap.
- PersistentMemoryAllocator::Reference histogram_ref = 0;
- std::unique_ptr<HistogramBase> tentative_histogram;
- PersistentHistogramAllocator* allocator = GlobalHistogramAllocator::Get();
- if (allocator) {
- tentative_histogram = allocator->AllocateHistogram(
- SPARSE_HISTOGRAM, name, 0, 0, nullptr, flags, &histogram_ref);
- }
- // Handle the case where no persistent allocator is present or the
- // persistent allocation fails (perhaps because it is full).
- if (!tentative_histogram) {
- DCHECK(!histogram_ref); // Should never have been set.
- DCHECK(!allocator); // Shouldn't have failed.
- flags &= ~HistogramBase::kIsPersistent;
- tentative_histogram.reset(new SparseHistogram(GetPermanentName(name)));
- tentative_histogram->SetFlags(flags);
- }
- // Register this histogram with the StatisticsRecorder. Keep a copy of
- // the pointer value to tell later whether the locally created histogram
- // was registered or deleted. The type is "void" because it could point
- // to released memory after the following line.
- const void* tentative_histogram_ptr = tentative_histogram.get();
- histogram = StatisticsRecorder::RegisterOrDeleteDuplicate(
- tentative_histogram.release());
- // Persistent histograms need some follow-up processing.
- if (histogram_ref) {
- allocator->FinalizeHistogram(histogram_ref,
- histogram == tentative_histogram_ptr);
- }
- }
- CHECK_EQ(SPARSE_HISTOGRAM, histogram->GetHistogramType());
- return histogram;
- }
- // static
- std::unique_ptr<HistogramBase> SparseHistogram::PersistentCreate(
- PersistentHistogramAllocator* allocator,
- const char* name,
- HistogramSamples::Metadata* meta,
- HistogramSamples::Metadata* logged_meta) {
- return WrapUnique(new SparseHistogram(allocator, name, meta, logged_meta));
- }
- SparseHistogram::~SparseHistogram() = default;
- uint64_t SparseHistogram::name_hash() const {
- return unlogged_samples_->id();
- }
- HistogramType SparseHistogram::GetHistogramType() const {
- return SPARSE_HISTOGRAM;
- }
- bool SparseHistogram::HasConstructionArguments(
- Sample expected_minimum,
- Sample expected_maximum,
- size_t expected_bucket_count) const {
- // SparseHistogram never has min/max/bucket_count limit.
- return false;
- }
- void SparseHistogram::Add(Sample value) {
- AddCount(value, 1);
- }
- void SparseHistogram::AddCount(Sample value, int count) {
- if (count <= 0) {
- NOTREACHED();
- return;
- }
- {
- base::AutoLock auto_lock(lock_);
- unlogged_samples_->Accumulate(value, count);
- }
- if (UNLIKELY(StatisticsRecorder::have_active_callbacks()))
- FindAndRunCallbacks(value);
- }
- std::unique_ptr<HistogramSamples> SparseHistogram::SnapshotSamples() const {
- std::unique_ptr<SampleMap> snapshot(new SampleMap(name_hash()));
- base::AutoLock auto_lock(lock_);
- snapshot->Add(*unlogged_samples_);
- snapshot->Add(*logged_samples_);
- return std::move(snapshot);
- }
- std::unique_ptr<HistogramSamples> SparseHistogram::SnapshotDelta() {
- DCHECK(!final_delta_created_);
- std::unique_ptr<SampleMap> snapshot(new SampleMap(name_hash()));
- base::AutoLock auto_lock(lock_);
- snapshot->Add(*unlogged_samples_);
- unlogged_samples_->Subtract(*snapshot);
- logged_samples_->Add(*snapshot);
- return std::move(snapshot);
- }
- std::unique_ptr<HistogramSamples> SparseHistogram::SnapshotFinalDelta() const {
- DCHECK(!final_delta_created_);
- final_delta_created_ = true;
- std::unique_ptr<SampleMap> snapshot(new SampleMap(name_hash()));
- base::AutoLock auto_lock(lock_);
- snapshot->Add(*unlogged_samples_);
- return std::move(snapshot);
- }
- void SparseHistogram::AddSamples(const HistogramSamples& samples) {
- base::AutoLock auto_lock(lock_);
- unlogged_samples_->Add(samples);
- }
- bool SparseHistogram::AddSamplesFromPickle(PickleIterator* iter) {
- base::AutoLock auto_lock(lock_);
- return unlogged_samples_->AddFromPickle(iter);
- }
- base::Value::Dict SparseHistogram::ToGraphDict() const {
- std::unique_ptr<HistogramSamples> snapshot = SnapshotSamples();
- return snapshot->ToGraphDict(histogram_name(), flags());
- }
- void SparseHistogram::SerializeInfoImpl(Pickle* pickle) const {
- pickle->WriteString(histogram_name());
- pickle->WriteInt(flags());
- }
- SparseHistogram::SparseHistogram(const char* name)
- : HistogramBase(name),
- unlogged_samples_(new SampleMap(HashMetricName(name))),
- logged_samples_(new SampleMap(unlogged_samples_->id())) {}
- SparseHistogram::SparseHistogram(PersistentHistogramAllocator* allocator,
- const char* name,
- HistogramSamples::Metadata* meta,
- HistogramSamples::Metadata* logged_meta)
- : HistogramBase(name),
- // While other histogram types maintain a static vector of values with
- // sufficient space for both "active" and "logged" samples, with each
- // SampleVector being given the appropriate half, sparse histograms
- // have no such initial allocation. Each sample has its own record
- // attached to a single PersistentSampleMap by a common 64-bit identifier.
- // Since a sparse histogram has two sample maps (active and logged),
- // there must be two sets of sample records with diffent IDs. The
- // "active" samples use, for convenience purposes, an ID matching
- // that of the histogram while the "logged" samples use that number
- // plus 1.
- unlogged_samples_(
- new PersistentSampleMap(HashMetricName(name), allocator, meta)),
- logged_samples_(new PersistentSampleMap(unlogged_samples_->id() + 1,
- allocator,
- logged_meta)) {}
- HistogramBase* SparseHistogram::DeserializeInfoImpl(PickleIterator* iter) {
- std::string histogram_name;
- int flags;
- if (!iter->ReadString(&histogram_name) || !iter->ReadInt(&flags)) {
- DLOG(ERROR) << "Pickle error decoding Histogram: " << histogram_name;
- return nullptr;
- }
- flags &= ~HistogramBase::kIPCSerializationSourceFlag;
- return SparseHistogram::FactoryGet(histogram_name, flags);
- }
- Value::Dict SparseHistogram::GetParameters() const {
- // Unlike Histogram::GetParameters, only set the type here, and no other
- // params. The other params do not make sense for sparse histograms.
- Value::Dict params;
- params.Set("type", HistogramTypeToString(GetHistogramType()));
- return params;
- }
- } // namespace base
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