| <HTML> |
| <BODY> |
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| <H2>Overview</H2> |
| This directory contains a simple example that sums values in a tree. |
| The example exhibits some speedup, but not a lot, because it quickly saturates |
| the system bus on a multiprocessor. For good speedup, there needs to be |
| more computation cycles per memory reference. The point of the example |
| is to teach how to use the raw task interface, so the computation is |
| deliberately trivial. |
| <P> |
| The performance of this example is better when objects are allocated |
| by the Threading Building Blocks scalable_allocator instead of |
| the default "operator new". The reason is that the scalable_allocator typically |
| packs small objects more tightly than the default "operator new", resulting in |
| a smaller memory footprint, and thus more efficient use of cache and virtual memory. |
| In addition, the scalable_allocator performs better for multi-threaded allocations. |
| </P> |
| <H2>Files</H2> |
| <DL> |
| <DT><A HREF="SerialSumTree.cpp">SerialSumTree.cpp</A> |
| <DD>Sums sequentially. |
| <DT><A HREF="SimpleParallelSumTree.cpp">SimpleParallelSumTree.cpp</A><DT> |
| <DD>Sums in parallel without any fancy tricks. |
| <DT><A HREF="OptimizedParallelSumTree.cpp">OptimizedParallelSumTree.cpp</A><DT> |
| <DD>Sums in parallel, using "recycling" and "continuation-passing" tricks. |
| In this case, it is only slightly faster than the simple version. |
| <DT><A HREF="common.h">common.h</A> |
| <DD>Shared declarations. |
| <DT><A HREF="main.cpp">main.cpp</A> |
| <DD>Driver. |
| <DT><A HREF="Makefile">Makefile</A> |
| <DD>Makefile for building example. |
| </DL> |
| |
| <H2>Directories</H2> |
| <DL> |
| <DT><A HREF="msvs">msvs</A> |
| <DD>Contains Microsoft* Visual Studio* 2005 workspace for building and running the example. |
| <DT><A HREF="xcode">xcode</A> |
| <DD>Contains Xcode* IDE workspace for building and running the example. |
| </DL> |
| |
| <H2>To Build</H2> |
| General build directions can be found <A HREF=../../index.html#build>here</A>. |
| <P></P> |
| |
| <H2>Usage</H2> |
| <DL> |
| <DT><TT>tree_sum [-stdmalloc] <I>S</I> <I>N</I></TT> |
| <DD><I>S</I> is the problem size (the number of nodes in the tree). |
| <I>N</I> is the number of threads to be used. |
| <BR> |
| Passing "-stdmalloc" as the 1st parameter causes the default "operator new" |
| to be used for memory allocations instead of the TBB scalable_allocator. |
| |
| <DT>To run a short version of this example, e.g., for use with Intel® Threading Tools: |
| <DD>Build a <I>debug</I> version of the example |
| (see the <A HREF=../../index.html#build>build directions</A>). |
| <BR>Run it with a small problem size and the desired number of threads, e.g., <TT>tree_sum 100000 4</TT>. |
| </DL> |
| |
| <HR> |
| <A HREF="../index.html">Up to parent directory</A> |
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| Copyright © 2005-2010 Intel Corporation. All Rights Reserved. |
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| Intel, Pentium, Intel Xeon, Itanium, Intel XScale and VTune are |
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