Program Listing for File timer.hpp

↰ Return to documentation for file (SeQuant/core/timer.hpp)

//
// Created by Eduard Valeyev on 3/28/18.
//

#ifndef SEQUANT_TIMER_HPP
#define SEQUANT_TIMER_HPP

#include <chrono>
#include <iostream>

namespace sequant {

template <size_t N = 1>
class TimerPool {
 public:
  typedef std::chrono::duration<double> dur_t;
  typedef std::chrono::high_resolution_clock clock_t;
  typedef std::chrono::time_point<clock_t> time_point_t;

  TimerPool() {
    clear();
    set_now_overhead(0);
  }

  static time_point_t now() { return clock_t::now(); }

  void set_now_overhead(size_t ns) { overhead_ = std::chrono::nanoseconds(ns); }

  void start(size_t t = 0) { tstart_[t] = now(); }
  dur_t stop(size_t t = 0) {
    const auto tstop = now();
    const dur_t result = (tstop - tstart_[t]) - overhead_;
    timers_[t] += result;
    return result;
  }
  double read(size_t t = 0) const { return timers_[t].count(); }
  void clear() {
    for (auto t = 0; t != ntimers; ++t) {
      timers_[t] = dur_t::zero();
      tstart_[t] = time_point_t();
    }
  }

 private:
  constexpr static auto ntimers = N;
  dur_t timers_[ntimers];
  time_point_t tstart_[ntimers];
  dur_t overhead_;  // the duration of now() call ... use this to automatically
  // adjust reported timings is you need fine-grained timing
};

}  // namespace sequant

#define SEQUANT_PROFILE_SINGLE(id, call)                       \
  {                                                            \
    sequant::TimerPool<> timer;                                \
    timer.start();                                             \
    { call; }                                                  \
    timer.stop();                                              \
    auto elapsed_seconds = timer.read();                       \
    std::wcout << id << ": elapsed_time = " << std::scientific \
               << elapsed_seconds << " seconds" << std::endl;  \
  }

#endif  // SEQUANT_TIMER_HPP