cc/debug/lap_timer.h

   1 // Copyright 2014 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_DEBUG_LAP_TIMER_H_
   6 #define CC_DEBUG_LAP_TIMER_H_
   7
   8 #include "base/time/time.h"
   9 #include "cc/base/cc_export.h"
  10
  11 namespace cc {
  12
  13 // LapTimer is used to calculate average times per "Lap" in perf tests.
  14 // Current() reports the time since the last call to Start().
  15 // Store() adds the time since the last call to Start() to the accumulator, and
  16 // resets the start time to now. Stored() returns the accumulated time.
  17 // NextLap increments the lap counter, used in counting the per lap averages.
  18 // If you initialize the LapTimer with a non zero warmup_laps, it will ignore
  19 // the times for that many laps at the start.
  20 // If you set the time_limit then you can use HasTimeLimitExpired() to see if
  21 // the current accumulated time has crossed that threshold, with an optimization
  22 // that it only tests this every check_interval laps.
  23 class CC_EXPORT LapTimer {
  24  public:
  25   LapTimer(int warmup_laps, base::TimeDelta time_limit, int check_interval);
  26   // Resets the timer back to it's starting state.
  27   void Reset();
  28   // Sets the start point to now.
  29   void Start();
  30   // Returns true if there are no more warmup laps to do.
  31   bool IsWarmedUp();
  32   // Advance the lap counter and update the accumulated time.
  33   // The accumulated time is only updated every check_interval laps.
  34   // If accumulating then the start point will also be updated.
  35   void NextLap();
  36   // Returns true if the stored time has exceeded the time limit specified.
  37   // May cause a call to Store().
  38   bool HasTimeLimitExpired();
  39   // Returns true if all lap times have been timed. Only true every n'th
  40   // lap, where n = check_interval.
  41   bool HasTimedAllLaps();
  42   // The average milliseconds per lap.
  43   float MsPerLap();
  44   // The number of laps per second.
  45   float LapsPerSecond();
  46   // The number of laps recorded.
  47   int NumLaps();
  48
  49  private:
  50   base::TimeTicks start_time_;
  51   base::TimeDelta accumulator_;
  52   int num_laps_;
  53   int warmup_laps_;
  54   int remaining_warmups_;
  55   int remaining_no_check_laps_;
  56   base::TimeDelta time_limit_;
  57   int check_interval_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(LapTimer);
  60 };
  61
  62 }  // namespace cc
  63
  64 #endif  // CC_DEBUG_LAP_TIMER_H_