utils/benchmark/src/thread_timer.h

   1 #ifndef BENCHMARK_THREAD_TIMER_H
   2 #define BENCHMARK_THREAD_TIMER_H
   3
   4 #include "check.h"
   5 #include "timers.h"
   6
   7 namespace benchmark {
   8 namespace internal {
   9
  10 class ThreadTimer {
  11  public:
  12   ThreadTimer() = default;
  13
  14   // Called by each thread
  15   void StartTimer() {
  16     running_ = true;
  17     start_real_time_ = ChronoClockNow();
  18     start_cpu_time_ = ThreadCPUUsage();
  19   }
  20
  21   // Called by each thread
  22   void StopTimer() {
  23     CHECK(running_);
  24     running_ = false;
  25     real_time_used_ += ChronoClockNow() - start_real_time_;
  26     // Floating point error can result in the subtraction producing a negative
  27     // time. Guard against that.
  28     cpu_time_used_ += std::max<double>(ThreadCPUUsage() - start_cpu_time_, 0);
  29   }
  30
  31   // Called by each thread
  32   void SetIterationTime(double seconds) { manual_time_used_ += seconds; }
  33
  34   bool running() const { return running_; }
  35
  36   // REQUIRES: timer is not running
  37   double real_time_used() {
  38     CHECK(!running_);
  39     return real_time_used_;
  40   }
  41
  42   // REQUIRES: timer is not running
  43   double cpu_time_used() {
  44     CHECK(!running_);
  45     return cpu_time_used_;
  46   }
  47
  48   // REQUIRES: timer is not running
  49   double manual_time_used() {
  50     CHECK(!running_);
  51     return manual_time_used_;
  52   }
  53
  54  private:
  55   bool running_ = false;        // Is the timer running
  56   double start_real_time_ = 0;  // If running_
  57   double start_cpu_time_ = 0;   // If running_
  58
  59   // Accumulated time so far (does not contain current slice if running_)
  60   double real_time_used_ = 0;
  61   double cpu_time_used_ = 0;
  62   // Manually set iteration time. User sets this with SetIterationTime(seconds).
  63   double manual_time_used_ = 0;
  64 };
  65
  66 }  // namespace internal
  67 }  // namespace benchmark
  68
  69 #endif  // BENCHMARK_THREAD_TIMER_H