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// Copyright 2018 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.
#ifndef COMPONENTS_SCHEDULING_METRICS_TASK_DURATION_METRIC_REPORTER_H_
#define COMPONENTS_SCHEDULING_METRICS_TASK_DURATION_METRIC_REPORTER_H_
#include <memory>
#include "base/component_export.h"
#include "base/macros.h"
#include "base/metrics/histogram.h"
#include "base/time/time.h"
namespace base {
class HistogramBase;
}
namespace scheduling_metrics {
// A helper class to report total task runtime split by the different types of
// |TypeClass|. Only full seconds are reported. Note that partial seconds are
// rounded up/down, so that on average the correct value is reported when many
// reports are added.
//
// |TaskClass| is an enum which should have kClass field.
template <class TaskClass>
class TaskDurationMetricReporter {
public:
// Note that 1000*1000 is used to get microseconds precision.
explicit TaskDurationMetricReporter(const char* metric_name)
: value_per_type_histogram_(new base::ScaledLinearHistogram(
metric_name,
1,
static_cast<int>(TaskClass::kCount),
static_cast<int>(TaskClass::kCount) + 1,
1000 * 1000,
base::HistogramBase::kUmaTargetedHistogramFlag)){};
void RecordTask(TaskClass task_class, base::TimeDelta duration) {
DCHECK_LT(static_cast<int>(task_class),
static_cast<int>(TaskClass::kCount));
// To get mircoseconds precision, duration is converted to microseconds
// since |value_per_type_histogram_| is constructed with a scale of
// 1000*1000.
if (!duration.is_zero()) {
value_per_type_histogram_->AddScaledCount(
static_cast<int>(task_class),
base::saturated_cast<int>(duration.InMicroseconds()));
}
}
private:
std::unique_ptr<base::ScaledLinearHistogram> value_per_type_histogram_;
DISALLOW_COPY_AND_ASSIGN(TaskDurationMetricReporter);
};
} // namespace scheduling_metrics
#endif // COMPONENTS_SCHEDULING_METRICS_TASK_DURATION_METRIC_REPORTER_H_