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// boost cpu_timer_info.cpp ----------------------------------------------------------//
// Copyright Beman Dawes 2011
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
// See http://www.boost.org/libs/timer for documentation.
#include <boost/timer/timer.hpp>
#include <boost/chrono/chrono.hpp>
#include <boost/detail/lightweight_main.hpp>
#include <cstdlib> // for atol()
#include <iostream>
#include <locale>
using boost::timer::nanosecond_type;
using boost::timer::cpu_times;
using boost::timer::cpu_timer;
using boost::timer::auto_cpu_timer;
using std::cout; using std::endl;
int cpp_main( int argc, char * argv[] )
{
cout << '\n';
cout << "For cpu_times.wall, the underlying clock "
<< (boost::chrono::high_resolution_clock::is_steady
? "is steady. "
: "is not steady. "
)
<< "Steady clocks are defined by C++11 as clocks for which values "
"of time_point never decrease as physical time advances and for "
"which values of time_point advance at a steady rate relative to "
"real time. That is, the clock may not be adjusted.\n\n";
cpu_times start_time;
start_time.clear();
cpu_times current_time;
{
cpu_timer cpu;
cout << "measure boost::timer::cpu_timer resolution for user time..."
<< endl;
for (int i = 0; i < 3; ++i)
{
cpu.start();
start_time = cpu.elapsed();
current_time.user = start_time.user;
while (current_time.user == start_time.user)
{
current_time = cpu.elapsed();
}
cout << current_time.user - start_time.user << "ns\n";
}
}
{
cpu_timer cpu;
cout << "measure boost::timer::cpu_timer resolution for wall-clock time..."
<< endl;
for (int i = 0; i < 100; ++i)
{
cpu.start();
start_time.wall = cpu.elapsed().wall;
current_time.wall = start_time.wall;
while (current_time.wall == start_time.wall)
{
current_time.wall = cpu.elapsed().wall;
}
cout << current_time.wall - start_time.wall << "ns ";
}
}
return 0;
}
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