URL
https://opencores.org/ocsvn/openrisc/openrisc/trunk
Subversion Repositories openrisc
[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc4/] [libstdc++-v3/] [doc/] [html/] [manual/] [bk01pt12ch31s03.html] - Rev 424
Go to most recent revision | Compare with Previous | Blame | View Log
<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Using</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><meta name="keywords" content=" C++ , library , parallel " /><meta name="keywords" content=" ISO C++ , library " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="parallel_mode.html" title="Chapter 31. Parallel Mode" /><link rel="prev" href="bk01pt12ch31s02.html" title="Semantics" /><link rel="next" href="bk01pt12ch31s04.html" title="Design" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Using</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="bk01pt12ch31s02.html">Prev</a> </td><th width="60%" align="center">Chapter 31. Parallel Mode</th><td width="20%" align="right"> <a accesskey="n" href="bk01pt12ch31s04.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="Using"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.ext.parallel_mode.using"></a>Using</h2></div></div></div><div class="sect2" title="Prerequisite Compiler Flags"><div class="titlepage"><div><div><h3 class="title"><a id="parallel_mode.using.prereq_flags"></a>Prerequisite Compiler Flags</h3></div></div></div><p> Any use of parallel functionality requires additional compiler and runtime support, in particular support for OpenMP. Adding this support is not difficult: just compile your application with the compiler flag <code class="literal">-fopenmp</code>. This will link in <code class="code">libgomp</code>, the GNU OpenMP <a class="ulink" href="http://gcc.gnu.org/onlinedocs/libgomp" target="_top">implementation</a>, whose presence is mandatory. </p><p> In addition, hardware that supports atomic operations and a compiler capable of producing atomic operations is mandatory: GCC defaults to no support for atomic operations on some common hardware architectures. Activating atomic operations may require explicit compiler flags on some targets (like sparc and x86), such as <code class="literal">-march=i686</code>, <code class="literal">-march=native</code> or <code class="literal">-mcpu=v9</code>. See the GCC manual for more information. </p></div><div class="sect2" title="Using Parallel Mode"><div class="titlepage"><div><div><h3 class="title"><a id="parallel_mode.using.parallel_mode"></a>Using Parallel Mode</h3></div></div></div><p> To use the libstdc++ parallel mode, compile your application with the prerequisite flags as detailed above, and in addition add <code class="constant">-D_GLIBCXX_PARALLEL</code>. This will convert all use of the standard (sequential) algorithms to the appropriate parallel equivalents. Please note that this doesn't necessarily mean that everything will end up being executed in a parallel manner, but rather that the heuristics and settings coded into the parallel versions will be used to determine if all, some, or no algorithms will be executed using parallel variants. </p><p>Note that the <code class="constant">_GLIBCXX_PARALLEL</code> define may change the sizes and behavior of standard class templates such as <code class="function">std::search</code>, and therefore one can only link code compiled with parallel mode and code compiled without parallel mode if no instantiation of a container is passed between the two translation units. Parallel mode functionality has distinct linkage, and cannot be confused with normal mode symbols. </p></div><div class="sect2" title="Using Specific Parallel Components"><div class="titlepage"><div><div><h3 class="title"><a id="parallel_mode.using.specific"></a>Using Specific Parallel Components</h3></div></div></div><p>When it is not feasible to recompile your entire application, or only specific algorithms need to be parallel-aware, individual parallel algorithms can be made available explicitly. These parallel algorithms are functionally equivalent to the standard drop-in algorithms used in parallel mode, but they are available in a separate namespace as GNU extensions and may be used in programs compiled with either release mode or with parallel mode. </p><p>An example of using a parallel version of <code class="function">std::sort</code>, but no other parallel algorithms, is: </p><pre class="programlisting"> #include <vector> #include <parallel/algorithm> int main() { std::vector<int> v(100); // ... // Explicitly force a call to parallel sort. __gnu_parallel::sort(v.begin(), v.end()); return 0; } </pre><p> Then compile this code with the prerequisite compiler flags (<code class="literal">-fopenmp</code> and any necessary architecture-specific flags for atomic operations.) </p><p> The following table provides the names and headers of all the parallel algorithms that can be used in a similar manner: </p><div class="table"><a id="id713517"></a><p class="title"><b>Table 31.1. Parallel Algorithms</b></p><div class="table-contents"><table summary="Parallel Algorithms" border="1"><colgroup><col align="left" /><col align="left" /><col align="left" /><col align="left" /></colgroup><thead><tr><th align="left">Algorithm</th><th align="left">Header</th><th align="left">Parallel algorithm</th><th align="left">Parallel header</th></tr></thead><tbody><tr><td align="left"><code class="function">std::accumulate</code></td><td align="left"><code class="filename">numeric</code></td><td align="left"><code class="function">__gnu_parallel::accumulate</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr><tr><td align="left"><code class="function">std::adjacent_difference</code></td><td align="left"><code class="filename">numeric</code></td><td align="left"><code class="function">__gnu_parallel::adjacent_difference</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr><tr><td align="left"><code class="function">std::inner_product</code></td><td align="left"><code class="filename">numeric</code></td><td align="left"><code class="function">__gnu_parallel::inner_product</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr><tr><td align="left"><code class="function">std::partial_sum</code></td><td align="left"><code class="filename">numeric</code></td><td align="left"><code class="function">__gnu_parallel::partial_sum</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr><tr><td align="left"><code class="function">std::adjacent_find</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::adjacent_find</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::count</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::count</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::count_if</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::count_if</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::equal</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::equal</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::find</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::find</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::find_if</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::find_if</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::find_first_of</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::find_first_of</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::for_each</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::for_each</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::generate</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::generate</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::generate_n</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::generate_n</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::lexicographical_compare</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::lexicographical_compare</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::mismatch</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::mismatch</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::search</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::search</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::search_n</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::search_n</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::transform</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::transform</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::replace</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::replace</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::replace_if</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::replace_if</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::max_element</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::max_element</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::merge</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::merge</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::min_element</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::min_element</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::nth_element</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::nth_element</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::partial_sort</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::partial_sort</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::partition</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::partition</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::random_shuffle</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::random_shuffle</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::set_union</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::set_union</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::set_intersection</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::set_intersection</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::set_symmetric_difference</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::set_symmetric_difference</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::set_difference</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::set_difference</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::sort</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::sort</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::stable_sort</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::stable_sort</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr><tr><td align="left"><code class="function">std::unique_copy</code></td><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="function">__gnu_parallel::unique_copy</code></td><td align="left"><code class="filename">parallel/algorithm</code></td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="bk01pt12ch31s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="parallel_mode.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="bk01pt12ch31s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Semantics </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> Design</td></tr></table></div></body></html>
Go to most recent revision | Compare with Previous | Blame | View Log