Mercurial > hg > js-dsp-test

diff fft/fftw/fftw-3.3.4/doc/html/Avoiding-MPI-Deadlocks.html @ 19:26056e866c29

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add FFTW to comparison table
author Chris Cannam
date Tue, 06 Oct 2015 13:08:39 +0100
parents
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fft/fftw/fftw-3.3.4/doc/html/Avoiding-MPI-Deadlocks.html	Tue Oct 06 13:08:39 2015 +0100
@@ -0,0 +1,80 @@
+<html lang="en">
+<head>
+<title>Avoiding MPI Deadlocks - FFTW 3.3.4</title>
+<meta http-equiv="Content-Type" content="text/html">
+<meta name="description" content="FFTW 3.3.4">
+<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 3.3.4, 20 September 2013).
+
+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-420"></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-421"></a><a name="index-MPI_005fBarrier-422"></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-423"></a><a name="index-fftw_005fdestroy_005fplan-424"></a><a name="index-fftw_005fflops-425"></a>
+<!--  -->
+
+   </body></html>
+