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