diff options
Diffstat (limited to 'doc/html/mpi/design.html')
| -rw-r--r-- | doc/html/mpi/design.html | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/doc/html/mpi/design.html b/doc/html/mpi/design.html new file mode 100644 index 0000000000..9d41e88b71 --- /dev/null +++ b/doc/html/mpi/design.html @@ -0,0 +1,79 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Design Philosophy</title> +<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> +<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> +<link rel="up" href="../mpi.html" title="Chapter 26. Boost.MPI"> +<link rel="prev" href="python.html" title="Python Bindings"> +<link rel="next" href="performance.html" title="Performance Evaluation"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table cellpadding="2" width="100%"><tr> +<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> +<td align="center"><a href="../../../index.html">Home</a></td> +<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> +<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> +<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> +<td align="center"><a href="../../../more/index.htm">More</a></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="python.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../mpi.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="performance.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="mpi.design"></a><a class="link" href="design.html" title="Design Philosophy">Design Philosophy</a> +</h2></div></div></div> +<p> + The design philosophy of the Parallel MPI library is very simple: be both convenient + and efficient. MPI is a library built for high-performance applications, but + it's FORTRAN-centric, performance-minded design makes it rather inflexible + from the C++ point of view: passing a string from one process to another is + inconvenient, requiring several messages and explicit buffering; passing a + container of strings from one process to another requires an extra level of + manual bookkeeping; and passing a map from strings to containers of strings + is positively infuriating. The Parallel MPI library allows all of these data + types to be passed using the same simple <code class="computeroutput"><span class="identifier">send</span><span class="special">()</span></code> and <code class="computeroutput"><span class="identifier">recv</span><span class="special">()</span></code> primitives. Likewise, collective operations + such as <code class="computeroutput"><a class="link" href="../boost/mpi/reduce.html" title="Function reduce">reduce()</a></code> allow arbitrary data types + and function objects, much like the C++ Standard Library would. + </p> +<p> + The higher-level abstractions provided for convenience must not have an impact + on the performance of the application. For instance, sending an integer via + <code class="computeroutput"><span class="identifier">send</span></code> must be as efficient as + a call to <code class="computeroutput"><span class="identifier">MPI_Send</span></code>, which means + that it must be implemented by a simple call to <code class="computeroutput"><span class="identifier">MPI_Send</span></code>; + likewise, an integer <code class="computeroutput"><a class="link" href="../boost/mpi/reduce.html" title="Function reduce">reduce()</a></code> using <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">plus</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span></code> must + be implemented with a call to <code class="computeroutput"><span class="identifier">MPI_Reduce</span></code> + on integers using the <code class="computeroutput"><span class="identifier">MPI_SUM</span></code> + operation: anything less will impact performance. In essence, this is the "don't + pay for what you don't use" principle: if the user is not transmitting + strings, s/he should not pay the overhead associated with strings. + </p> +<p> + Sometimes, achieving maximal performance means foregoing convenient abstractions + and implementing certain functionality using lower-level primitives. For this + reason, it is always possible to extract enough information from the abstractions + in Boost.MPI to minimize the amount of effort required to interface between + Boost.MPI and the C MPI library. + </p> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2005-2007 Douglas Gregor, + Matthias Troyer, Trustees of Indiana University<p> + Distributed under the Boost Software License, Version 1.0. (See accompanying + file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> + http://www.boost.org/LICENSE_1_0.txt </ulink>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="python.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../mpi.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="performance.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |