118 lines
4.2 KiB
C++
118 lines
4.2 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/metrics/histogram_snapshot_manager.h"
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#include "base/memory/scoped_ptr.h"
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#include "base/metrics/histogram_flattener.h"
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#include "base/metrics/histogram_samples.h"
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#include "base/metrics/statistics_recorder.h"
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#include "base/stl_util.h"
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using std::map;
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using std::string;
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namespace base {
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HistogramSnapshotManager::HistogramSnapshotManager(
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HistogramFlattener* histogram_flattener)
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: histogram_flattener_(histogram_flattener) {
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DCHECK(histogram_flattener_);
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}
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HistogramSnapshotManager::~HistogramSnapshotManager() {
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STLDeleteValues(&logged_samples_);
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}
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void HistogramSnapshotManager::PrepareDeltas(HistogramBase::Flags flag_to_set,
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bool record_only_uma) {
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StatisticsRecorder::Histograms histograms;
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StatisticsRecorder::GetHistograms(&histograms);
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for (StatisticsRecorder::Histograms::const_iterator it = histograms.begin();
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histograms.end() != it;
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++it) {
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(*it)->SetFlags(flag_to_set);
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if (record_only_uma &&
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0 == ((*it)->flags() & Histogram::kUmaTargetedHistogramFlag))
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continue;
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PrepareDelta(**it);
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}
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}
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void HistogramSnapshotManager::PrepareDelta(const HistogramBase& histogram) {
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DCHECK(histogram_flattener_);
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// Get up-to-date snapshot of sample stats.
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scoped_ptr<HistogramSamples> snapshot(histogram.SnapshotSamples());
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const std::string& histogram_name = histogram.histogram_name();
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int corruption = histogram.FindCorruption(*snapshot);
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// Crash if we detect that our histograms have been overwritten. This may be
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// a fair distance from the memory smasher, but we hope to correlate these
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// crashes with other events, such as plugins, or usage patterns, etc.
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if (HistogramBase::BUCKET_ORDER_ERROR & corruption) {
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// The checksum should have caught this, so crash separately if it didn't.
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CHECK_NE(0, HistogramBase::RANGE_CHECKSUM_ERROR & corruption);
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CHECK(false); // Crash for the bucket order corruption.
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}
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// Checksum corruption might not have caused order corruption.
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CHECK_EQ(0, HistogramBase::RANGE_CHECKSUM_ERROR & corruption);
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// Note, at this point corruption can only be COUNT_HIGH_ERROR or
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// COUNT_LOW_ERROR and they never arise together, so we don't need to extract
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// bits from corruption.
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if (corruption) {
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DLOG(ERROR) << "Histogram: " << histogram_name
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<< " has data corruption: " << corruption;
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histogram_flattener_->InconsistencyDetected(
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static_cast<HistogramBase::Inconsistency>(corruption));
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// Don't record corrupt data to metrics services.
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int old_corruption = inconsistencies_[histogram_name];
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if (old_corruption == (corruption | old_corruption))
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return; // We've already seen this corruption for this histogram.
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inconsistencies_[histogram_name] |= corruption;
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histogram_flattener_->UniqueInconsistencyDetected(
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static_cast<HistogramBase::Inconsistency>(corruption));
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return;
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}
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HistogramSamples* to_log;
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map<string, HistogramSamples*>::iterator it =
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logged_samples_.find(histogram_name);
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if (it == logged_samples_.end()) {
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to_log = snapshot.release();
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// This histogram has not been logged before, add a new entry.
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logged_samples_[histogram_name] = to_log;
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} else {
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HistogramSamples* already_logged = it->second;
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InspectLoggedSamplesInconsistency(*snapshot, already_logged);
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snapshot->Subtract(*already_logged);
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already_logged->Add(*snapshot);
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to_log = snapshot.get();
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}
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if (to_log->redundant_count() > 0)
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histogram_flattener_->RecordDelta(histogram, *to_log);
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}
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void HistogramSnapshotManager::InspectLoggedSamplesInconsistency(
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const HistogramSamples& new_snapshot,
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HistogramSamples* logged_samples) {
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HistogramBase::Count discrepancy =
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logged_samples->TotalCount() - logged_samples->redundant_count();
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if (!discrepancy)
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return;
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histogram_flattener_->InconsistencyDetectedInLoggedCount(discrepancy);
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if (discrepancy > Histogram::kCommonRaceBasedCountMismatch) {
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// Fix logged_samples.
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logged_samples->Subtract(*logged_samples);
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logged_samples->Add(new_snapshot);
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}
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}
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} // namespace base
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