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<title>Qt 4.8: ClockCycleCounter.cpp Example File (demos/spectrum/3rdparty/fftreal/stopwatch/ClockCycleCounter.cpp)</title>
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<h1 class="title">ClockCycleCounter.cpp Example File</h1>
<span class="small-subtitle">demos/spectrum/3rdparty/fftreal/stopwatch/ClockCycleCounter.cpp</span>
<!-- $$$demos/spectrum/3rdparty/fftreal/stopwatch/ClockCycleCounter.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/*****************************************************************************
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***********************************************************************/</span>
<span class="preprocessor">#if defined (_MSC_VER)</span>
<span class="preprocessor">#pragma warning (1 : 4130) // "'operator' : logical operation on address of string constant"</span>
<span class="preprocessor">#pragma warning (1 : 4223) // "nonstandard extension used : non-lvalue array converted to pointer"</span>
<span class="preprocessor">#pragma warning (1 : 4705) // "statement has no effect"</span>
<span class="preprocessor">#pragma warning (1 : 4706) // "assignment within conditional expression"</span>
<span class="preprocessor">#pragma warning (4 : 4786) // "identifier was truncated to '255' characters in the debug information"</span>
<span class="preprocessor">#pragma warning (4 : 4800) // "forcing value to bool 'true' or 'false' (performance warning)"</span>
<span class="preprocessor">#pragma warning (4 : 4355) // "'this' : used in base member initializer list"</span>
<span class="preprocessor">#endif</span>
<span class="comment">/*\\\ INCLUDE FILES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/</span>
<span class="preprocessor">#include "ClockCycleCounter.h"</span>
<span class="preprocessor">#include <cassert></span>
<span class="keyword">namespace</span> stopwatch
{
<span class="comment">/*\\\ PUBLIC \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/</span>
<span class="comment">/*
==============================================================================
Name: ctor
Description:
The first object constructed initialise global data. This first
construction may be a bit slow.
Throws: Nothing
==============================================================================
*/</span>
ClockCycleCounter<span class="operator">::</span>ClockCycleCounter ()
: _start_time (<span class="number">0</span>)
<span class="operator">,</span> _state (<span class="number">0</span>)
<span class="operator">,</span> _best_score (<span class="operator">-</span><span class="number">1</span>)
{
<span class="keyword">if</span> (<span class="operator">!</span> _init_flag)
{
<span class="comment">// Should be executed in this order</span>
compute_clk_mul ();
compute_measure_time_total ();
compute_measure_time_lap ();
<span class="comment">// Restores object state</span>
_start_time <span class="operator">=</span> <span class="number">0</span>;
_state <span class="operator">=</span> <span class="number">0</span>;
_best_score <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
_init_flag <span class="operator">=</span> <span class="keyword">true</span>;
}
}
<span class="comment">/*
==============================================================================
Name: get_time_total
Description:
Gives the time elapsed between the latest stop_lap() and start() calls.
Returns:
The duration, in clock cycles.
Throws: Nothing
==============================================================================
*/</span>
Int64 ClockCycleCounter<span class="operator">::</span>get_time_total () <span class="keyword">const</span>
{
<span class="keyword">const</span> Int64 duration <span class="operator">=</span> _state <span class="operator">-</span> _start_time;
assert (duration <span class="operator">></span><span class="operator">=</span> <span class="number">0</span>);
<span class="keyword">const</span> Int64 t <span class="operator">=</span> max (
duration <span class="operator">-</span> _measure_time_total<span class="operator">,</span>
<span class="keyword">static_cast</span> <span class="operator"><</span>Int64<span class="operator">></span> (<span class="number">0</span>)
);
<span class="keyword">return</span> (t <span class="operator">*</span> _clk_mul);
}
<span class="comment">/*
==============================================================================
Name: get_time_best_lap
Description:
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.
Returns:
The smallest duration, in clock cycles.
Throws: Nothing
==============================================================================
*/</span>
Int64 ClockCycleCounter<span class="operator">::</span>get_time_best_lap () <span class="keyword">const</span>
{
assert (_best_score <span class="operator">></span><span class="operator">=</span> <span class="number">0</span>);
<span class="keyword">const</span> Int64 t1 <span class="operator">=</span> max (
_best_score <span class="operator">-</span> _measure_time_lap<span class="operator">,</span>
<span class="keyword">static_cast</span> <span class="operator"><</span>Int64<span class="operator">></span> (<span class="number">0</span>)
);
<span class="keyword">const</span> Int64 t <span class="operator">=</span> min (t1<span class="operator">,</span> get_time_total ());
<span class="keyword">return</span> (t <span class="operator">*</span> _clk_mul);
}
<span class="comment">/*\\\ PROTECTED \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/</span>
<span class="comment">/*\\\ PRIVATE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/</span>
<span class="preprocessor">#if defined (__MACOS__)</span>
<span class="keyword">static</span> <span class="keyword">inline</span> <span class="type">double</span> stopwatch_ClockCycleCounter_get_time_s ()
{
<span class="keyword">const</span> Nanoseconds ns <span class="operator">=</span> AbsoluteToNanoseconds (UpTime ());
<span class="keyword">return</span> (ns<span class="operator">.</span>hi <span class="operator">*</span> <span class="number">4294967296e</span><span class="operator">-</span><span class="number">9</span> <span class="operator">+</span> ns<span class="operator">.</span>lo <span class="operator">*</span> <span class="number">1e</span><span class="operator">-</span><span class="number">9</span>);
}
<span class="preprocessor">#endif // __MACOS__</span>
<span class="comment">/*
==============================================================================
Name: compute_clk_mul
Description:
This function, only for PowerPC/MacOS computers, computes the multiplier
required to deduce clock cycles from the internal counter.
Throws: Nothing
==============================================================================
*/</span>
<span class="type">void</span> ClockCycleCounter<span class="operator">::</span>compute_clk_mul ()
{
assert (<span class="operator">!</span> _init_flag);
<span class="preprocessor">#if defined (__MACOS__)</span>
<span class="type">long</span> clk_speed_mhz <span class="operator">=</span> CurrentProcessorSpeed ();
<span class="keyword">const</span> Int64 clk_speed <span class="operator">=</span>
<span class="keyword">static_cast</span> <span class="operator"><</span>Int64<span class="operator">></span> (clk_speed_mhz) <span class="operator">*</span> (<span class="number">1000L</span><span class="operator">*</span><span class="number">1000L</span>);
<span class="keyword">const</span> <span class="type">double</span> start_time_s <span class="operator">=</span> stopwatch_ClockCycleCounter_get_time_s ();
start ();
<span class="keyword">const</span> <span class="type">double</span> duration <span class="operator">=</span> <span class="number">0.01</span>; <span class="comment">// Seconds</span>
<span class="keyword">while</span> (stopwatch_ClockCycleCounter_get_time_s () <span class="operator">-</span> start_time_s <span class="operator"><</span> duration)
{
<span class="keyword">continue</span>;
}
<span class="keyword">const</span> <span class="type">double</span> stop_time_s <span class="operator">=</span> stopwatch_ClockCycleCounter_get_time_s ();
stop ();
<span class="keyword">const</span> <span class="type">double</span> diff_time_s <span class="operator">=</span> stop_time_s <span class="operator">-</span> start_time_s;
<span class="keyword">const</span> <span class="type">double</span> nbr_cycles <span class="operator">=</span> diff_time_s <span class="operator">*</span> <span class="keyword">static_cast</span> <span class="operator"><</span><span class="type">double</span><span class="operator">></span> (clk_speed);
<span class="keyword">const</span> Int64 diff_time_c <span class="operator">=</span> _state <span class="operator">-</span> _start_time;
<span class="keyword">const</span> <span class="type">double</span> clk_mul <span class="operator">=</span> nbr_cycles <span class="operator">/</span> <span class="keyword">static_cast</span> <span class="operator"><</span><span class="type">double</span><span class="operator">></span> (diff_time_c);
_clk_mul <span class="operator">=</span> round_int (clk_mul);
<span class="preprocessor">#endif // __MACOS__</span>
}
<span class="type">void</span> ClockCycleCounter<span class="operator">::</span>compute_measure_time_total ()
{
start ();
spend_time ();
Int64 best_result <span class="operator">=</span> <span class="number">0x7FFFFFFFL</span>; <span class="comment">// Should be enough</span>
<span class="type">long</span> nbr_tests <span class="operator">=</span> <span class="number">100</span>;
<span class="keyword">for</span> (<span class="type">long</span> cnt <span class="operator">=</span> <span class="number">0</span>; cnt <span class="operator"><</span> nbr_tests; <span class="operator">+</span><span class="operator">+</span>cnt)
{
start ();
stop_lap ();
<span class="keyword">const</span> Int64 duration <span class="operator">=</span> _state <span class="operator">-</span> _start_time;
best_result <span class="operator">=</span> min (best_result<span class="operator">,</span> duration);
}
_measure_time_total <span class="operator">=</span> best_result;
}
<span class="comment">/*
==============================================================================
Name: compute_measure_time_lap
Description:
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 subtracting
the measurement duration).
Throws: Nothing
==============================================================================
*/</span>
<span class="type">void</span> ClockCycleCounter<span class="operator">::</span>compute_measure_time_lap ()
{
start ();
spend_time ();
<span class="type">long</span> nbr_tests <span class="operator">=</span> <span class="number">10</span>;
<span class="keyword">for</span> (<span class="type">long</span> cnt <span class="operator">=</span> <span class="number">0</span>; cnt <span class="operator"><</span> nbr_tests; <span class="operator">+</span><span class="operator">+</span>cnt)
{
stop_lap ();
stop_lap ();
stop_lap ();
stop_lap ();
}
_measure_time_lap <span class="operator">=</span> _best_score;
}
<span class="type">void</span> ClockCycleCounter<span class="operator">::</span>spend_time ()
{
<span class="keyword">const</span> Int64 nbr_clocks <span class="operator">=</span> <span class="number">500</span>; <span class="comment">// Number of clock cycles to spend</span>
<span class="keyword">const</span> Int64 start <span class="operator">=</span> read_clock_counter ();
Int64 current;
<span class="keyword">do</span>
{
current <span class="operator">=</span> read_clock_counter ();
}
<span class="keyword">while</span> ((current <span class="operator">-</span> start) <span class="operator">*</span> _clk_mul <span class="operator"><</span> nbr_clocks);
}
Int64 ClockCycleCounter<span class="operator">::</span>_measure_time_total <span class="operator">=</span> <span class="number">0</span>;
Int64 ClockCycleCounter<span class="operator">::</span>_measure_time_lap <span class="operator">=</span> <span class="number">0</span>;
<span class="type">int</span> ClockCycleCounter<span class="operator">::</span>_clk_mul <span class="operator">=</span> <span class="number">1</span>;
<span class="type">bool</span> ClockCycleCounter<span class="operator">::</span>_init_flag <span class="operator">=</span> <span class="keyword">false</span>;
} <span class="comment">// namespace stopwatch</span>
<span class="comment">/*\\\ EOF \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/</span></pre>
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<!-- @@@demos/spectrum/3rdparty/fftreal/stopwatch/ClockCycleCounter.cpp -->
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