components/scheduling_metrics/total_duration_metric_reporter.h

   1 // Copyright 2018 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_SCHEDULING_METRICS_TOTAL_DURATION_METRIC_REPORTER_H_
   6 #define COMPONENTS_SCHEDULING_METRICS_TOTAL_DURATION_METRIC_REPORTER_H_
   7
   8 #include "base/component_export.h"
   9 #include "base/metrics/histogram.h"
  10 #include "base/optional.h"
  11 #include "base/time/time.h"
  12
  13 namespace scheduling_metrics {
  14
  15 // Helper class to measure the total duration of the event accounting for
  16 // possibility of the renderer process going away at any point.
  17 //
  18 // This is implemented by "undoing" old total value and "applying" new one
  19 // each time RecordAdditionalDuration() is called.
  20 // "Undoing" is implemented by having a second "negative" histogram, so to
  21 // obtain the result, |positive_histogram - negative_histogram| difference
  22 // should be analysed.
  23 class COMPONENT_EXPORT(SCHEDULING_METRICS) TotalDurationMetricReporter {
  24  public:
  25   TotalDurationMetricReporter(const char* positive_histogram_name,
  26                               const char* negative_histogram_name);
  27
  28   void RecordAdditionalDuration(base::TimeDelta duration);
  29
  30   void Reset();
  31
  32  private:
  33   base::Optional<base::TimeDelta> reported_value_;
  34
  35   base::HistogramBase* positive_histogram_;
  36   base::HistogramBase* negative_histogram_;
  37 };
  38
  39 }  // namespace scheduling_metrics
  40
  41 #endif  // COMPONENTS_SCHEDULING_METRICS_TOTAL_DURATION_METRIC_REPORTER_H_