/*****************************************************************************
ClockCycleCounter.cpp
Copyright (c) 2003 Laurent de Soras
--- Legal stuff ---
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*Tab=3***********************************************************************/
#if defined (_MSC_VER)#pragma warning (1 : 4130) // "'operator' : logical operation on address of string constant"#pragma warning (1 : 4223) // "nonstandard extension used : non-lvalue array converted to pointer"#pragma warning (1 : 4705) // "statement has no effect"#pragma warning (1 : 4706) // "assignment within conditional expression"#pragma warning (4 : 4786) // "identifier was truncated to '255' characters in the debug information"#pragma warning (4 : 4800) // "forcing value to bool 'true' or 'false' (performance warning)"#pragma warning (4 : 4355) // "'this' : used in base member initializer list"#endif/*\\\ INCLUDE FILES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/#include "ClockCycleCounter.h"#include <cassert>namespace stopwatch
{
/*\\\ PUBLIC \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*//*
==============================================================================
Name: ctor
描述：
The first object constructed initialise global data. This first
construction may be a bit slow.
Throws: Nothing
==============================================================================
*/
ClockCycleCounter::ClockCycleCounter ()
: _start_time (0)
, _state (0)
, _best_score (-1)
{
if (! _init_flag)
{
// Should be executed in this order
compute_clk_mul ();
compute_measure_time_total ();
compute_measure_time_lap ();
// Restores object state
_start_time =0;
_state =0;
_best_score =-1;
_init_flag =true;
}
}
/*
==============================================================================
Name: get_time_total
描述：
Gives the time elapsed between the latest stop_lap() and start() calls.
返回：
The duration, in clock cycles.
Throws: Nothing
==============================================================================
*/
Int64 ClockCycleCounter::get_time_total () const
{
const Int64 duration = _state - _start_time;
assert (duration >=0);
const Int64 t = max (
duration - _measure_time_total,static_cast<Int64> (0)
);
return (t * _clk_mul);
}
/*
==============================================================================
Name: get_time_best_lap
描述：
Gives the smallest time between two consecutive stop_lap() or between
the stop_lap() and start(). The value is reset by a call to start().
Call this function only after a stop_lap().
The time is amputed from the duration of the stop_lap() call itself.
返回：
The smallest duration, in clock cycles.
Throws: Nothing
==============================================================================
*/
Int64 ClockCycleCounter::get_time_best_lap () const
{
assert (_best_score >=0);
const Int64 t1 = max (
_best_score - _measure_time_lap,static_cast<Int64> (0)
);
const Int64 t = min (t1, get_time_total ());
return (t * _clk_mul);
}
/*\\\ PROTECTED \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*//*\\\ PRIVATE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/#if defined (__MACOS__)staticinlinedouble stopwatch_ClockCycleCounter_get_time_s ()
{
const Nanoseconds ns = AbsoluteToNanoseconds (UpTime ());
return (ns.hi *4294967296e-9+ ns.lo *1e-9);
}
#endif // __MACOS__/*
==============================================================================
Name: compute_clk_mul
描述：
This function, only for PowerPC/MacOS computers, computes the multiplier
required to deduce clock cycles from the internal counter.
Throws: Nothing
==============================================================================
*/void ClockCycleCounter::compute_clk_mul ()
{
assert (! _init_flag);
#if defined (__MACOS__)long clk_speed_mhz = CurrentProcessorSpeed ();
const Int64 clk_speed =static_cast<Int64> (clk_speed_mhz) * (1000L*1000L);
constdouble start_time_s = stopwatch_ClockCycleCounter_get_time_s ();
start ();
constdouble duration =0.01; // Secondswhile (stopwatch_ClockCycleCounter_get_time_s () - start_time_s < duration)
{
continue;
}
constdouble stop_time_s = stopwatch_ClockCycleCounter_get_time_s ();
stop ();
constdouble diff_time_s = stop_time_s - start_time_s;
constdouble nbr_cycles = diff_time_s *static_cast<double> (clk_speed);
const Int64 diff_time_c = _state - _start_time;
constdouble clk_mul = nbr_cycles /static_cast<double> (diff_time_c);
_clk_mul = round_int (clk_mul);
#endif // __MACOS__
}
void ClockCycleCounter::compute_measure_time_total ()
{
start ();
spend_time ();
Int64 best_result =0x7FFFFFFFL; // Should be enoughlong nbr_tests =100;
for (long cnt =0; cnt < nbr_tests; ++cnt)
{
start ();
stop_lap ();
const Int64 duration = _state - _start_time;
best_result = min (best_result, duration);
}
_measure_time_total = best_result;
}
/*
==============================================================================
Name: compute_measure_time_lap
描述：
Computes the duration of one stop_lap() call and store it. It will be used
later to get the real duration of the measured operation (by substracting
the measurement duration).
Throws: Nothing
==============================================================================
*/void ClockCycleCounter::compute_measure_time_lap ()
{
start ();
spend_time ();
long nbr_tests =10;
for (long cnt =0; cnt < nbr_tests; ++cnt)
{
stop_lap ();
stop_lap ();
stop_lap ();
stop_lap ();
}
_measure_time_lap = _best_score;
}
void ClockCycleCounter::spend_time ()
{
const Int64 nbr_clocks =500; // Number of clock cycles to spendconst Int64 start = read_clock_counter ();
Int64 current;
do
{
current = read_clock_counter ();
}
while ((current - start) * _clk_mul < nbr_clocks);
}
Int64 ClockCycleCounter::_measure_time_total =0;
Int64 ClockCycleCounter::_measure_time_lap =0;
int ClockCycleCounter::_clk_mul =1;
bool ClockCycleCounter::_init_flag =false;
} // namespace stopwatch/*\\\ EOF \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
