mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-05 12:25:05 +00:00
97 lines
4.3 KiB
HTML
97 lines
4.3 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- This manual is for FFTW
|
||
|
|
(version 3.3.10, 10 December 2020).
|
||
|
|
|
||
|
|
Copyright (C) 2003 Matteo Frigo.
|
||
|
|
|
||
|
|
Copyright (C) 2003 Massachusetts Institute of Technology.
|
||
|
|
|
||
|
|
Permission is granted to make and distribute verbatim copies of this
|
||
|
|
manual provided the copyright notice and this permission notice are
|
||
|
|
preserved on all copies.
|
||
|
|
|
||
|
|
Permission is granted to copy and distribute modified versions of this
|
||
|
|
manual under the conditions for verbatim copying, provided that the
|
||
|
|
entire resulting derived work is distributed under the terms of a
|
||
|
|
permission notice identical to this one.
|
||
|
|
|
||
|
|
Permission is granted to copy and distribute translations of this manual
|
||
|
|
into another language, under the above conditions for modified versions,
|
||
|
|
except that this permission notice may be stated in a translation
|
||
|
|
approved by the Free Software Foundation. -->
|
||
|
|
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<title>Avoiding MPI Deadlocks (FFTW 3.3.10)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Avoiding MPI Deadlocks (FFTW 3.3.10)">
|
||
|
|
<meta name="keywords" content="Avoiding MPI Deadlocks (FFTW 3.3.10)">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<link href="index.html" rel="start" title="Top">
|
||
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Distributed_002dmemory-FFTW-with-MPI.html" rel="up" title="Distributed-memory FFTW with MPI">
|
||
|
|
<link href="FFTW-MPI-Performance-Tips.html" rel="next" title="FFTW MPI Performance Tips">
|
||
|
|
<link href="FFTW-MPI-Wisdom.html" rel="prev" title="FFTW MPI Wisdom">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.indentedblock {margin-right: 0em}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style: oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
span.nolinebreak {white-space: nowrap}
|
||
|
|
span.roman {font-family: initial; font-weight: normal}
|
||
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<span id="Avoiding-MPI-Deadlocks"></span><div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="FFTW-MPI-Performance-Tips.html" accesskey="n" rel="next">FFTW MPI Performance Tips</a>, Previous: <a href="FFTW-MPI-Wisdom.html" accesskey="p" rel="prev">FFTW MPI Wisdom</a>, Up: <a href="Distributed_002dmemory-FFTW-with-MPI.html" accesskey="u" rel="up">Distributed-memory FFTW with MPI</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<span id="Avoiding-MPI-Deadlocks-1"></span><h3 class="section">6.9 Avoiding MPI Deadlocks</h3>
|
||
|
|
<span id="index-deadlock"></span>
|
||
|
|
|
||
|
|
<p>An MPI program can <em>deadlock</em> if one process is waiting for a
|
||
|
|
message from another process that never gets sent. To avoid deadlocks
|
||
|
|
when using FFTW’s MPI routines, it is important to know which
|
||
|
|
functions are <em>collective</em>: that is, which functions must
|
||
|
|
<em>always</em> be called in the <em>same order</em> from <em>every</em>
|
||
|
|
process in a given communicator. (For example, <code>MPI_Barrier</code> is
|
||
|
|
the canonical example of a collective function in the MPI standard.)
|
||
|
|
<span id="index-collective-function-2"></span>
|
||
|
|
<span id="index-MPI_005fBarrier"></span>
|
||
|
|
</p>
|
||
|
|
|
||
|
|
<p>The functions in FFTW that are <em>always</em> collective are: every
|
||
|
|
function beginning with ‘<samp>fftw_mpi_plan</samp>’, as well as
|
||
|
|
<code>fftw_mpi_broadcast_wisdom</code> and <code>fftw_mpi_gather_wisdom</code>.
|
||
|
|
Also, the following functions from the ordinary FFTW interface are
|
||
|
|
collective when they are applied to a plan created by an
|
||
|
|
‘<samp>fftw_mpi_plan</samp>’ function: <code>fftw_execute</code>,
|
||
|
|
<code>fftw_destroy_plan</code>, and <code>fftw_flops</code>.
|
||
|
|
<span id="index-fftw_005fexecute-4"></span>
|
||
|
|
<span id="index-fftw_005fdestroy_005fplan-2"></span>
|
||
|
|
<span id="index-fftw_005fflops-1"></span>
|
||
|
|
</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|