Mercurial > hg > sv-dependency-builds

diff src/fftw-3.3.3/doc/html/Avoiding-MPI-Deadlocks.html @ 10:37bf6b4a2645

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add FFTW3
author Chris Cannam
date Wed, 20 Mar 2013 15:35:50 +0000
parents
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fftw-3.3.3/doc/html/Avoiding-MPI-Deadlocks.html	Wed Mar 20 15:35:50 2013 +0000
@@ -0,0 +1,80 @@
+<html lang="en">
+<head>
+<title>Avoiding MPI Deadlocks - FFTW 3.3.3</title>
+<meta http-equiv="Content-Type" content="text/html">
+<meta name="description" content="FFTW 3.3.3">
+<meta name="generator" content="makeinfo 4.13">
+<link title="Top" rel="start" href="index.html#Top">
+<link rel="up" href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" title="Distributed-memory FFTW with MPI">
+<link rel="prev" href="FFTW-MPI-Wisdom.html#FFTW-MPI-Wisdom" title="FFTW MPI Wisdom">
+<link rel="next" href="FFTW-MPI-Performance-Tips.html#FFTW-MPI-Performance-Tips" title="FFTW MPI Performance Tips">
+<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
+<!--
+This manual is for FFTW
+(version 3.3.3, 25 November 2012).
+
+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.
+   -->
+<meta http-equiv="Content-Style-Type" content="text/css">
+<style type="text/css"><!--
+  pre.display { font-family:inherit }
+  pre.format  { font-family:inherit }
+  pre.smalldisplay { font-family:inherit; font-size:smaller }
+  pre.smallformat  { font-family:inherit; font-size:smaller }
+  pre.smallexample { font-size:smaller }
+  pre.smalllisp    { font-size:smaller }
+  span.sc    { font-variant:small-caps }
+  span.roman { font-family:serif; font-weight:normal; } 
+  span.sansserif { font-family:sans-serif; font-weight:normal; } 
+--></style>
+</head>
+<body>
+<div class="node">
+<a name="Avoiding-MPI-Deadlocks"></a>
+<p>
+Next:&nbsp;<a rel="next" accesskey="n" href="FFTW-MPI-Performance-Tips.html#FFTW-MPI-Performance-Tips">FFTW MPI Performance Tips</a>,
+Previous:&nbsp;<a rel="previous" accesskey="p" href="FFTW-MPI-Wisdom.html#FFTW-MPI-Wisdom">FFTW MPI Wisdom</a>,
+Up:&nbsp;<a rel="up" accesskey="u" href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI">Distributed-memory FFTW with MPI</a>
+<hr>
+</div>
+
+<h3 class="section">6.9 Avoiding MPI Deadlocks</h3>
+
+<p><a name="index-deadlock-417"></a>
+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.) 
+<a name="index-collective-function-418"></a><a name="index-MPI_005fBarrier-419"></a>
+
+   <p>The functions in FFTW that are <em>always</em> collective are: every
+function beginning with &lsquo;<samp><span class="samp">fftw_mpi_plan</span></samp>&rsquo;, 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
+&lsquo;<samp><span class="samp">fftw_mpi_plan</span></samp>&rsquo; function: <code>fftw_execute</code>,
+<code>fftw_destroy_plan</code>, and <code>fftw_flops</code>. 
+<a name="index-fftw_005fexecute-420"></a><a name="index-fftw_005fdestroy_005fplan-421"></a><a name="index-fftw_005fflops-422"></a>
+<!--  -->
+
+   </body></html>
+