ceph/src/boost/libs/chrono/stopwatches/example/stopwatch_example.cpp

   1 //  example/stopwatch_example.cpp  ---------------------------------------------------//
   2 //  Copyright Beman Dawes 2006, 2008
   3 //  Copyright 2009-2011 Vicente J. Botet Escriba
   4 //  Copyright (c) Microsoft Corporation 2014
   5 //  Distributed under the Boost Software License, Version 1.0.
   6 //  See http://www.boost.org/LICENSE_1_0.txt
   7 //  See http://www.boost.org/libs/chrono/stopwatches for documentation.
   8
   9 #include <iostream>
  10 #include <boost/chrono/stopwatches/strict_stopwatch.hpp>
  11 #include <boost/chrono/chrono_io.hpp>
  12 #include <boost/chrono/process_cpu_clocks.hpp>
  13 #include <cmath>
  14
  15 using namespace boost::chrono;
  16
  17 #ifdef BOOST_CHRONO_HAS_PROCESS_CLOCKS
  18 #if ! BOOST_OS_WINDOWS || BOOST_PLAT_WINDOWS_DESKTOP
  19 typedef process_cpu_clock clock_type;
  20 #else
  21 // Windows store doesn't support process_cpu_clock, default to high_resolution_clock.
  22 typedef high_resolution_clock clock_type;
  23 #endif
  24 #else
  25 typedef high_resolution_clock clock_type;
  26 #endif
  27
  28 namespace ex
  29 {
  30     template<class Rep, class Period>
  31     void sleep_for(const duration<Rep, Period>& d)
  32     {
  33       typedef high_resolution_clock Clock;
  34       typename Clock::time_point go =
  35           Clock::now() + d;
  36       while (Clock::now() < go)
  37       {
  38       }
  39     }
  40 }
  41
  42 int f1(long j)
  43 {
  44   strict_stopwatch<clock_type> sw;
  45
  46   for ( long i = 0; i < j; ++i )
  47     std::sqrt( 123.456L );  // burn some time
  48   ex::sleep_for(milliseconds(100));
  49
  50   std::cout << "f1("<< j <<") Elapsed time: " << sw.elapsed() << std::endl;
  51   return 0;
  52 }
  53 int main()
  54 {
  55   strict_stopwatch<clock_type> sw;
  56
  57   f1(1000);
  58   f1(2000);
  59   f1(3000);
  60 #ifdef BOOST_CHRONO_HAS_PROCESS_CLOCKS2
  61   std::cout << "main() Elapsed time: " << duration_cast<duration<process_times<double>,boost::ratio<1> > >(sw.elapsed()) << std::endl;
  62   std::cout << "main() Elapsed time: " << duration_cast<duration<process_times<nanoseconds::rep>,boost::milli> >(sw.elapsed()) << std::endl;
  63 #endif
  64   std::cout << "main() Elapsed time: " << sw.elapsed() << std::endl;
  65   return 0;
  66 }