1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
<!DOCTYPE html>
<html class="writer-html5" lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>5.2. Open MPI extensions — Open MPI 5.0.8 documentation</title>
<link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
<link rel="stylesheet" type="text/css" href="../_static/css/theme.css" />
<!--[if lt IE 9]>
<script src="../_static/js/html5shiv.min.js"></script>
<![endif]-->
<script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
<script src="../_static/jquery.js"></script>
<script src="../_static/underscore.js"></script>
<script src="../_static/_sphinx_javascript_frameworks_compat.js"></script>
<script src="../_static/doctools.js"></script>
<script src="../_static/sphinx_highlight.js"></script>
<script src="../_static/js/theme.js"></script>
<link rel="index" title="Index" href="../genindex.html" />
<link rel="search" title="Search" href="../search.html" />
<link rel="next" title="5.3. User-Level Fault Mitigation (ULFM)" href="ulfm.html" />
<link rel="prev" title="5.1. Open MPI profiling interface" href="profiling.html" />
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search" >
<a href="../index.html" class="icon icon-home">
Open MPI
</a>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
<input type="text" name="q" placeholder="Search docs" aria-label="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu">
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="../quickstart.html">1. Quick start</a></li>
<li class="toctree-l1"><a class="reference internal" href="../getting-help.html">2. Getting help</a></li>
<li class="toctree-l1"><a class="reference internal" href="../release-notes/index.html">3. Release notes</a></li>
<li class="toctree-l1"><a class="reference internal" href="../installing-open-mpi/index.html">4. Building and installing Open MPI</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="index.html">5. Open MPI-specific features</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="profiling.html">5.1. Open MPI profiling interface</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">5.2. Open MPI extensions</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#available-extensions">5.2.1. Available extensions</a></li>
<li class="toctree-l3"><a class="reference internal" href="#compiling-the-extensions">5.2.2. Compiling the extensions</a></li>
<li class="toctree-l3"><a class="reference internal" href="#using-the-extensions">5.2.3. Using the extensions</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="ulfm.html">5.3. User-Level Fault Mitigation (ULFM)</a></li>
<li class="toctree-l2"><a class="reference internal" href="java.html">5.4. Open MPI Java bindings</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../validate.html">6. Validating your installation</a></li>
<li class="toctree-l1"><a class="reference internal" href="../version-numbering.html">7. Version numbers and compatibility</a></li>
<li class="toctree-l1"><a class="reference internal" href="../mca.html">8. The Modular Component Architecture (MCA)</a></li>
<li class="toctree-l1"><a class="reference internal" href="../building-apps/index.html">9. Building MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../launching-apps/index.html">10. Launching MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../tuning-apps/index.html">11. Run-time operation and tuning MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../app-debug/index.html">12. Debugging Open MPI Parallel Applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../developers/index.html">13. Developer’s guide</a></li>
<li class="toctree-l1"><a class="reference internal" href="../contributing.html">14. Contributing to Open MPI</a></li>
<li class="toctree-l1"><a class="reference internal" href="../license/index.html">15. License</a></li>
<li class="toctree-l1"><a class="reference internal" href="../history.html">16. History of Open MPI</a></li>
<li class="toctree-l1"><a class="reference internal" href="../man-openmpi/index.html">17. Open MPI manual pages</a></li>
<li class="toctree-l1"><a class="reference internal" href="../man-openshmem/index.html">18. OpenSHMEM manual pages</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"><nav class="wy-nav-top" aria-label="Mobile navigation menu" >
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="../index.html">Open MPI</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="Page navigation">
<ul class="wy-breadcrumbs">
<li><a href="../index.html" class="icon icon-home" aria-label="Home"></a></li>
<li class="breadcrumb-item"><a href="index.html"><span class="section-number">5. </span>Open MPI-specific features</a></li>
<li class="breadcrumb-item active"><span class="section-number">5.2. </span>Open MPI extensions</li>
<li class="wy-breadcrumbs-aside">
<a href="../_sources/features/extensions.rst.txt" rel="nofollow"> View page source</a>
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<style>
.wy-table-responsive table td,.wy-table-responsive table th{white-space:normal}
</style><div class="section" id="open-mpi-extensions">
<span id="ompi-features-extentions-label"></span><h1><span class="section-number">5.2. </span>Open MPI extensions<a class="headerlink" href="#open-mpi-extensions" title="Permalink to this heading"></a></h1>
<p>Open MPI contains a framework for extending the MPI API that is
available to applications. Each extension is usually a standalone set
of functionality that is distinct from other extensions (similar to
how Open MPI’s plugins are usually unrelated to each other). These
extensions provide new functions and/or constants that are available
to MPI applications.</p>
<div class="admonition warning">
<p class="admonition-title">Warning</p>
<p>These extensions are neither standard nor portable to
other MPI implementations!</p>
<p>They are a mechanism for the Open MPI developer community to
provide new functionality to users, typically before it becomes
standardized by the MPI Forum.</p>
</div>
<div class="section" id="available-extensions">
<h2><span class="section-number">5.2.1. </span>Available extensions<a class="headerlink" href="#available-extensions" title="Permalink to this heading"></a></h2>
<p>The following extensions are included in this version of Open MPI:</p>
<ol class="arabic simple">
<li><p><code class="docutils literal notranslate"><span class="pre">shortfloat</span></code>: Provides MPI datatypes <code class="docutils literal notranslate"><span class="pre">MPIX_C_FLOAT16</span></code>,
<code class="docutils literal notranslate"><span class="pre">MPIX_SHORT_FLOAT</span></code>, <code class="docutils literal notranslate"><span class="pre">MPIX_SHORT_FLOAT</span></code>, and
<code class="docutils literal notranslate"><span class="pre">MPIX_CXX_SHORT_FLOAT_COMPLEX</span></code> if corresponding language types are
available. See <code class="docutils literal notranslate"><span class="pre">ompi/mpiext/shortfloat/README.txt</span></code> for details.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">affinity</span></code>: Provides the <code class="docutils literal notranslate"><span class="pre">OMPI_Affinity_str()</span></code> API, which returns
a string indicating the resources which a process is bound. For
more details, see its man page.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">cuda</span></code>: When the library is compiled with CUDA-aware support, it
provides two things. First, a macro
<code class="docutils literal notranslate"><span class="pre">MPIX_CUDA_AWARE_SUPPORT</span></code>. Secondly, the function
<code class="docutils literal notranslate"><span class="pre">MPIX_Query_cuda_support()</span></code> that can be used to query for support.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">example</span></code>: A non-functional extension; its only purpose is to
provide an example for how to create other extensions.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">ftmpi</span></code>: An implementation of the User Level Fault Mitigation
(ULFM) proposal. <a class="reference internal" href="ulfm.html#ulfm-label"><span class="std std-ref">See its documentation section</span></a>
for more details.</p></li>
</ol>
</div>
<div class="section" id="compiling-the-extensions">
<h2><span class="section-number">5.2.2. </span>Compiling the extensions<a class="headerlink" href="#compiling-the-extensions" title="Permalink to this heading"></a></h2>
<p>Open MPI extensions are all enabled by default; they can be disabled
via the <code class="docutils literal notranslate"><span class="pre">--disable-mpi-ext</span></code> command line switch.</p>
<p>Since extensions are meant to be used by advanced users only, this
file does not document which extensions are available or what they do.
Look in the <code class="docutils literal notranslate"><span class="pre">ompi/mpiext</span></code> directory in a distribution Open MPI
tarball to see the extensions; each subdirectory of that directory
contains an extension. Each has a <code class="docutils literal notranslate"><span class="pre">README</span></code> file that describes what
it does.</p>
</div>
<div class="section" id="using-the-extensions">
<h2><span class="section-number">5.2.3. </span>Using the extensions<a class="headerlink" href="#using-the-extensions" title="Permalink to this heading"></a></h2>
<p>To reinforce the fact that these extensions are non-standard, you must
include a separate header file after <code class="docutils literal notranslate"><span class="pre"><mpi.h></span></code> to obtain the function
prototypes, constant declarations, etc. For example:</p>
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="cp">#include</span><span class="w"> </span><span class="cpf"><mpi.h></span>
<span class="cp">#if defined(OPEN_MPI) && OPEN_MPI</span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf"><mpi-ext.h></span>
<span class="cp">#endif</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">MPI_Init</span><span class="p">(</span><span class="nb">NULL</span><span class="p">,</span><span class="w"> </span><span class="nb">NULL</span><span class="p">);</span>
<span class="cp">#if defined(OPEN_MPI) && OPEN_MPI</span>
<span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="n">ompi_bound</span><span class="p">[</span><span class="n">OMPI_AFFINITY_STRING_MAX</span><span class="p">];</span>
<span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="n">current_binding</span><span class="p">[</span><span class="n">OMPI_AFFINITY_STRING_MAX</span><span class="p">];</span>
<span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="n">exists</span><span class="p">[</span><span class="n">OMPI_AFFINITY_STRING_MAX</span><span class="p">];</span>
<span class="w"> </span><span class="n">OMPI_Affinity_str</span><span class="p">(</span><span class="n">OMPI_AFFINITY_LAYOUT_FMT</span><span class="p">,</span><span class="w"> </span><span class="n">ompi_bound</span><span class="p">,</span>
<span class="w"> </span><span class="n">current_bindings</span><span class="p">,</span><span class="w"> </span><span class="n">exists</span><span class="p">);</span>
<span class="cp">#endif</span>
<span class="w"> </span><span class="n">MPI_Finalize</span><span class="p">();</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span>
<span class="p">}</span>
</pre></div>
</div>
<p>Notice that the Open MPI-specific code is surrounded by the <code class="docutils literal notranslate"><span class="pre">#if</span></code>
statement to ensure that it is only ever compiled by Open MPI.</p>
<p>The Open MPI wrapper compilers (<code class="docutils literal notranslate"><span class="pre">mpicc</span></code> and friends) should
automatically insert all relevant compiler and linker flags necessary
to use the extensions. No special flags or steps should be necessary
compared to “normal” MPI applications.</p>
</div>
</div>
</div>
</div>
<footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
<a href="profiling.html" class="btn btn-neutral float-left" title="5.1. Open MPI profiling interface" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
<a href="ulfm.html" class="btn btn-neutral float-right" title="5.3. User-Level Fault Mitigation (ULFM)" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
</div>
<hr/>
<div role="contentinfo">
<p>© Copyright 2003-2025, The Open MPI Community.
<span class="lastupdated">Last updated on 2025-05-30 16:41:43 UTC.
</span></p>
</div>
Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a
<a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a>
provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script>
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
</body>
</html>
|
