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Wenzel Jakob
77 lines
3.3 KiB
HTML
77 lines
3.3 KiB
HTML
<HTML>
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<BODY>
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<H2>Overview</H2>
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This directory contains a simple example that sums values in a tree.
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The example exhibits some speedup, but not a lot, because it quickly saturates
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the system bus on a multiprocessor. For good speedup, there needs to be
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more computation cycles per memory reference. The point of the example
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is to teach how to use the raw task interface, so the computation is
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deliberately trivial.
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<P>
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The performance of this example is better when objects are allocated
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by the scalable_allocator instead of
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the default "operator new". The reason is that the scalable_allocator typically
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packs small objects more tightly than the default "operator new", resulting in
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a smaller memory footprint, and thus more efficient use of cache and virtual memory.
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In addition, the scalable_allocator performs better for multi-threaded allocations.
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</P>
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<H2>Files</H2>
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<DL>
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<DT><A HREF="SerialSumTree.cpp">SerialSumTree.cpp</A>
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<DD>Sums sequentially.
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<DT><A HREF="SimpleParallelSumTree.cpp">SimpleParallelSumTree.cpp</A><DT>
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<DD>Sums in parallel without any fancy tricks.
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<DT><A HREF="OptimizedParallelSumTree.cpp">OptimizedParallelSumTree.cpp</A><DT>
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<DD>Sums in parallel, using "recycling" and "continuation-passing" tricks.
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In this case, it is only slightly faster than the simple version.
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<DT><A HREF="common.h">common.h</A>
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<DD>Shared declarations.
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<DT><A HREF="main.cpp">main.cpp</A>
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<DD>Main program which parses command line options and runs the algorithm.
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<DT><A HREF="Makefile">Makefile</A>
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<DD>Makefile for building example.
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</DL>
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<H2>Directories</H2>
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<DL>
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<DT><A HREF="msvs">msvs</A>
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<DD>Contains Microsoft* Visual Studio* 2010 workspace for building and running the
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example (Windows* systems only).<DT><A HREF="xcode">xcode</A>
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<DD>Contains Xcode* IDE workspace for building and running the example (OS X*
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systems only).</DL>
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<H2>To Build</H2>
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General build directions can be found <A HREF=../../index.html#build>here</A>.
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<P></P>
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<H2>Usage</H2>
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<DL>
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<DT><TT>tree_sum <I>-h</I></TT>
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<DD>Prints the help for command line options
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<DT><TT>tree_sum [<I>n-of-threads</I>=value] [<I>number-of-nodes</I>=value] [<I>silent</I>] [<I>stdmalloc</I>]</TT>
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<DT><TT>tree_sum [<I>n-of-threads</I> [<I>number-of-nodes</I>]] [<I>silent</I>] [<I>stdmalloc</I>]</TT>
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<DD><I>n-of-threads</I> is the number of threads to use; a range of the form <I>low</I>[:<I>high</I>], where low and optional high are non-negative integers or 'auto' for the default.<BR>
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<I>number-of-nodes</I> is the number of nodes in the tree.<BR>
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<I>silent</I> - no output except elapsed time.<BR>
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<I>stdmalloc</I> - causes the default "operator new" to be used for memory allocations instead of the scalable_allocator.<BR>
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<DT>To run a short version of this example, e.g., for use with Intel® Parallel Inspector:
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<DD>Build a <I>debug</I> version of the example
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(see the <A HREF=../../index.html#build>build directions</A>).
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<BR>Run it with a small problem size and the desired number of threads, e.g., <TT>tree_sum 4 100000</TT>.
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</DL>
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<HR>
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<A HREF="../index.html">Up to parent directory</A>
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<p></p>
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Copyright © 2005-2016 Intel Corporation. All Rights Reserved.
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<P></P>
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Intel is a registered trademark or trademark of Intel Corporation
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or its subsidiaries in the United States and other countries.
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<p></p>
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* Other names and brands may be claimed as the property of others.
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</HTML>
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