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| <div class="section"> |
| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.karma.performance_measurements.numeric_performance.double_performance"></a><a class="link" href="double_performance.html" title="Comparing the performance of a single double_ generator">Comparing |
| the performance of a single double_ generator</a> |
| </h5></div></div></div> |
| <p> |
| These performance measurements are centered around default formatting |
| of a single <code class="computeroutput"><span class="keyword">double</span></code> floating |
| point number using different libraries and methods. The overall execution |
| times for those examples are compared below. We compare using <code class="computeroutput"><span class="identifier">sprintf</span></code>, C++ iostreams, <a href="../../../../../../../../libs/format/index.html" target="_top">Boost.Format</a>, |
| and <span class="emphasis"><em>Spirit.Karma</em></span>. |
| </p> |
| <p> |
| For the full source code of the performance test please see here: <a href="../../../../../../optimization/karma/double_performance.cpp" target="_top">double_performance.cpp</a>. |
| All the measurements have been done by executing <code class="computeroutput"><span class="number">1e6</span></code> |
| iterations for each formatting type (NUMITERATIONS is set to <code class="computeroutput"><span class="number">1e6</span></code> in the code shown below). |
| </p> |
| <p> |
| Code used to measure the performance for <code class="computeroutput"><span class="identifier">sprintf</span></code>: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">char</span> <span class="identifier">buffer</span><span class="special">[</span><span class="number">256</span><span class="special">];</span> |
| <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="identifier">NUMITERATIONS</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span> |
| <span class="identifier">sprintf</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="string">"%f"</span><span class="special">,</span> <span class="number">12345.12345</span><span class="special">);</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Code used to measure the performance for standard C++ iostreams: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">stringstream</span> <span class="identifier">strm</span><span class="special">;</span> |
| <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="identifier">NUMITERATIONS</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span> |
| <span class="identifier">strm</span><span class="special">.</span><span class="identifier">str</span><span class="special">(</span><span class="string">""</span><span class="special">);</span> |
| <span class="identifier">strm</span> <span class="special"><<</span> <span class="number">12345.12345</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Code used to measure the performance for <a href="../../../../../../../../libs/format/index.html" target="_top">Boost.Format</a>: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">generated</span><span class="special">;</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">format</span> <span class="identifier">double_format</span><span class="special">(</span><span class="string">"%f"</span><span class="special">);</span> |
| <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="identifier">NUMITERATIONS</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> |
| <span class="identifier">generated</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">str</span><span class="special">(</span><span class="identifier">double_format</span> <span class="special">%</span> <span class="number">12345.12345</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| The following code shows the common definitions used by all <span class="emphasis"><em>Spirit.Karma</em></span> |
| performance measurements as listed below: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">double_</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Code used to measure the performance for <span class="emphasis"><em>Spirit.Karma</em></span> |
| using a plain character buffer: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">char</span> <span class="identifier">buffer</span><span class="special">[</span><span class="number">256</span><span class="special">];</span> |
| <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="identifier">NUMITERATIONS</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span> |
| <span class="keyword">char</span> <span class="special">*</span><span class="identifier">p</span> <span class="special">=</span> <span class="identifier">buffer</span><span class="special">;</span> |
| <span class="identifier">generate</span><span class="special">(</span><span class="identifier">p</span><span class="special">,</span> <span class="identifier">double_</span><span class="special">,</span> <span class="number">12345.12345</span><span class="special">);</span> |
| <span class="special">*</span><span class="identifier">p</span> <span class="special">=</span> <span class="char">'\0'</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| The following table shows the overall performance results collected while |
| using different compilers. All times are in seconds measured for <code class="computeroutput"><span class="number">1e6</span></code> iterations (platform: Windows7, Intel |
| Core Duo(tm) Processor, 2.8GHz, 4GByte RAM). For a more readable comparison |
| of the results see this <a class="link" href="double_performance.html#spirit.karma.double_performance" title="Figure 4. Performance comparison for a single double">figure</a>. |
| </p> |
| <div class="table"> |
| <a name="id1112575"></a><p class="title"><b>Table 6. Performance comparison for a single double (all times in [s], |
| `1e6` iterations)</b></p> |
| <div class="table-contents"><table class="table" summary="Performance comparison for a single double (all times in [s], |
| `1e6` iterations)"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| <col> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Library |
| </p> |
| </th> |
| <th> |
| <p> |
| gcc 4.4.0 (32 bit) |
| </p> |
| </th> |
| <th> |
| <p> |
| VC++ 10 (32 bit) |
| </p> |
| </th> |
| <th> |
| <p> |
| Intel 11.1 (32 bit) |
| </p> |
| </th> |
| <th> |
| <p> |
| gcc 4.4.0 (64 bit) |
| </p> |
| </th> |
| <th> |
| <p> |
| VC++ 10 (64 bit) |
| </p> |
| </th> |
| <th> |
| <p> |
| Intel 11.1 (64 bit) |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| sprintf |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.755 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.965 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.880 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.713 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.807 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.694 |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| iostreams |
| </p> |
| </td> |
| <td> |
| <p> |
| 2.316 |
| </p> |
| </td> |
| <td> |
| <p> |
| 2.624 |
| </p> |
| </td> |
| <td> |
| <p> |
| 1.964 |
| </p> |
| </td> |
| <td> |
| <p> |
| 1.634 |
| </p> |
| </td> |
| <td> |
| <p> |
| 1.468 |
| </p> |
| </td> |
| <td> |
| <p> |
| 1.354 |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a href="../../../../../../../../libs/format/index.html" target="_top">Boost.Format</a> |
| </p> |
| </td> |
| <td> |
| <p> |
| 3.188 |
| </p> |
| </td> |
| <td> |
| <p> |
| 3.737 |
| </p> |
| </td> |
| <td> |
| <p> |
| 2.878 |
| </p> |
| </td> |
| <td> |
| <p> |
| 3.217 |
| </p> |
| </td> |
| <td> |
| <p> |
| 2.672 |
| </p> |
| </td> |
| <td> |
| <p> |
| 2.011 |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <span class="emphasis"><em>Spirit.Karma</em></span> double_ |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.813 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.561 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.368 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.426 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.260 |
| </p> |
| </td> |
| <td> |
| <p> |
| 0.218 |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <br class="table-break"><p> |
| </p> |
| <div class="figure"> |
| <a name="spirit.karma.double_performance"></a><p class="title"><b>Figure 4. Performance comparison for a single double</b></p> |
| <div class="figure-contents"><span class="inlinemediaobject"><img src="../../../.././images/double_performance.png" alt="Performance comparison for a single double"></span></div> |
| </div> |
| <p><br class="figure-break"> |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2001-2010 Joel de Guzman, Hartmut Kaiser<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
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