components/scheduler/renderer/task_cost_estimator.h

   1 // Copyright 2015 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_SCHEDULER_RENDERER_TASK_COST_ESTIMATOR_H_
   6 #define COMPONENTS_SCHEDULER_RENDERER_TASK_COST_ESTIMATOR_H_
   7
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/time/time.h"
  10 #include "cc/base/rolling_time_delta_history.h"
  11 #include "components/scheduler/scheduler_export.h"
  12
  13 namespace base {
  14 class TickClock;
  15 }
  16
  17 namespace scheduler {
  18
  19 // Estimates the cost of running tasks based on historical timing data.
  20 class SCHEDULER_EXPORT TaskCostEstimator
  21     : public base::MessageLoop::TaskObserver {
  22  public:
  23   TaskCostEstimator(int sample_count, double estimation_percentile);
  24   ~TaskCostEstimator() override;
  25
  26   base::TimeDelta expected_task_duration() const {
  27     return expected_task_duration_;
  28   }
  29
  30   // TaskObserver implementation:
  31   void WillProcessTask(const base::PendingTask& pending_task) override;
  32   void DidProcessTask(const base::PendingTask& pending_task) override;
  33
  34   void Clear();
  35
  36   void SetTimeSourceForTesting(scoped_ptr<base::TickClock> time_source);
  37
  38  private:
  39   cc::RollingTimeDeltaHistory rolling_time_delta_history_;
  40   scoped_ptr<base::TickClock> time_source_;
  41   int outstanding_task_count_;
  42   double estimation_percentile_;
  43   base::TimeTicks task_start_time_;
  44   base::TimeDelta expected_task_duration_;
  45
  46   DISALLOW_COPY_AND_ASSIGN(TaskCostEstimator);
  47 };
  48
  49 }  // namespace scheduler
  50
  51 #endif  // COMPONENTS_SCHEDULER_RENDERER_TASK_COST_ESTIMATOR_H_