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 scheduler {
  14
  15 // Estimates the cost of running tasks based on historical timing data.
  16 class SCHEDULER_EXPORT TaskCostEstimator
  17     : public base::MessageLoop::TaskObserver {
  18  public:
  19   TaskCostEstimator(int sample_count, double estimation_percentile);
  20   ~TaskCostEstimator() override;
  21
  22   base::TimeDelta expected_task_duration() const {
  23     return expected_task_duration_;
  24   }
  25
  26   // TaskObserver implementation:
  27   void WillProcessTask(const base::PendingTask& pending_task) override;
  28   void DidProcessTask(const base::PendingTask& pending_task) override;
  29
  30  protected:
  31   // Virtual for testing.
  32   virtual base::TimeTicks Now();
  33
  34  private:
  35   cc::RollingTimeDeltaHistory rolling_time_delta_history_;
  36   int outstanding_task_count_;
  37   double estimation_percentile_;
  38   base::TimeTicks task_start_time_;
  39   base::TimeDelta expected_task_duration_;
  40
  41   DISALLOW_COPY_AND_ASSIGN(TaskCostEstimator);
  42 };
  43
  44 }  // namespace scheduler
  45
  46 #endif  // COMPONENTS_SCHEDULER_RENDERER_TASK_COST_ESTIMATOR_H_