| // 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/histogram_snapshot_manager.h" |
| |
| #include "base/metrics/statistics_recorder.h" |
| |
| using base::Histogram; |
| using base::StatisticsRecorder; |
| |
| namespace base { |
| |
| HistogramSnapshotManager::HistogramSnapshotManager( |
| HistogramFlattener* histogram_flattener) |
| : histogram_flattener_(histogram_flattener) { |
| DCHECK(histogram_flattener_); |
| } |
| |
| HistogramSnapshotManager::~HistogramSnapshotManager() {} |
| |
| void HistogramSnapshotManager::PrepareDeltas(Histogram::Flags flag_to_set, |
| bool record_only_uma) { |
| StatisticsRecorder::Histograms histograms; |
| StatisticsRecorder::GetHistograms(&histograms); |
| for (StatisticsRecorder::Histograms::const_iterator it = histograms.begin(); |
| histograms.end() != it; |
| ++it) { |
| (*it)->SetFlags(flag_to_set); |
| if (record_only_uma && |
| 0 == ((*it)->flags() & Histogram::kUmaTargetedHistogramFlag)) |
| continue; |
| PrepareDelta(**it); |
| } |
| } |
| |
| void HistogramSnapshotManager::PrepareDelta(const Histogram& histogram) { |
| DCHECK(histogram_flattener_); |
| |
| // Get up-to-date snapshot of sample stats. |
| Histogram::SampleSet snapshot; |
| histogram.SnapshotSample(&snapshot); |
| const std::string& histogram_name = histogram.histogram_name(); |
| |
| int corruption = histogram.FindCorruption(snapshot); |
| |
| // Crash if we detect that our histograms have been overwritten. This may be |
| // a fair distance from the memory smasher, but we hope to correlate these |
| // crashes with other events, such as plugins, or usage patterns, etc. |
| if (Histogram::BUCKET_ORDER_ERROR & corruption) { |
| // The checksum should have caught this, so crash separately if it didn't. |
| CHECK_NE(0, Histogram::RANGE_CHECKSUM_ERROR & corruption); |
| CHECK(false); // Crash for the bucket order corruption. |
| } |
| // Checksum corruption might not have caused order corruption. |
| CHECK_EQ(0, Histogram::RANGE_CHECKSUM_ERROR & corruption); |
| |
| if (corruption) { |
| NOTREACHED(); |
| histogram_flattener_->InconsistencyDetected(corruption); |
| // Don't record corrupt data to metrics survices. |
| if (NULL == inconsistencies_.get()) |
| inconsistencies_.reset(new ProblemMap); |
| int old_corruption = (*inconsistencies_)[histogram_name]; |
| if (old_corruption == (corruption | old_corruption)) |
| return; // We've already seen this corruption for this histogram. |
| (*inconsistencies_)[histogram_name] |= corruption; |
| histogram_flattener_->UniqueInconsistencyDetected(corruption); |
| return; |
| } |
| |
| // Find the already recorded stats, or create an empty set. Remove from our |
| // snapshot anything that we've already recorded. |
| LoggedSampleMap::iterator it = logged_samples_.find(histogram_name); |
| Histogram::SampleSet* already_logged; |
| if (logged_samples_.end() == it) { |
| // Add new entry |
| already_logged = &logged_samples_[histogram.histogram_name()]; |
| already_logged->Resize(histogram); // Complete initialization. |
| } else { |
| already_logged = &(it->second); |
| int64 discrepancy(already_logged->TotalCount() - |
| already_logged->redundant_count()); |
| if (discrepancy) { |
| NOTREACHED(); // Already_logged has become corrupt. |
| int problem = static_cast<int>(discrepancy); |
| if (problem != discrepancy) |
| problem = INT_MAX; |
| histogram_flattener_->SnapshotProblemResolved(problem); |
| // With no valid baseline, we'll act like we've recorded everything in our |
| // snapshot. |
| already_logged->Subtract(*already_logged); |
| already_logged->Add(snapshot); |
| } |
| // Deduct any stats we've already logged from our snapshot. |
| snapshot.Subtract(*already_logged); |
| } |
| |
| // Snapshot now contains only a delta to what we've already_logged. |
| if (snapshot.redundant_count() > 0) { |
| histogram_flattener_->RecordDelta(histogram, snapshot); |
| // Add new data into our running total. |
| already_logged->Add(snapshot); |
| } |
| } |
| } // namespace base |