cc/test/lap_timer.h

   1 // Copyright 2013 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 CC_TEST_LAP_TIMER_H_
   6 #define CC_TEST_LAP_TIMER_H_
   7
   8 #include "base/time/time.h"
   9
  10 namespace cc {
  11
  12 // LapTimer is used to calculate average times per "Lap" in perf tests.
  13 // Current() reports the time since the last call to Start().
  14 // Store() adds the time since the last call to Start() to the accumulator, and
  15 // resets the start time to now. Stored() returns the accumulated time.
  16 // NextLap increments the lap counter, used in counting the per lap averages.
  17 // If you initialize the LapTimer with a non zero warmup_laps, it will ignore
  18 // the times for that many laps at the start.
  19 // If you set the time_limit then you can use HasTimeLimitExpired() to see if
  20 // the current accumulated time has crossed that threshold, with an optimization
  21 // that it only tests this every check_interval laps.
  22 class LapTimer {
  23  public:
  24   LapTimer(int warmup_laps, base::TimeDelta time_limit, int check_interval);
  25   // Resets the timer back to it's starting state.
  26   void Reset();
  27   // Sets the start point to now.
  28   void Start();
  29   // Returns true if there are no more warmup laps to do.
  30   bool IsWarmedUp();
  31   // Advance the lap counter and update the accumulated time.
  32   // The accumulated time is only updated every check_interval laps.
  33   // If accumulating then the start point will also be updated.
  34   void NextLap();
  35   // Returns true if the stored time has exceeded the time limit specified.
  36   // May cause a call to Store().
  37   bool HasTimeLimitExpired();
  38   // The average milliseconds per lap.
  39   float MsPerLap();
  40   // The number of laps per second.
  41   float LapsPerSecond();
  42   // The number of laps recorded.
  43   int NumLaps();
  44
  45  private:
  46   base::TimeTicks start_time_;
  47   base::TimeDelta accumulator_;
  48   int num_laps_;
  49   int warmup_laps_;
  50   int remaining_warmups_;
  51   base::TimeDelta time_limit_;
  52   int check_interval_;
  53   bool accumulated_;
  54
  55   DISALLOW_COPY_AND_ASSIGN(LapTimer);
  56 };
  57
  58 }  // namespace cc
  59
  60 #endif  // CC_TEST_LAP_TIMER_H_