[176] | 1 | <?xml version="1.0" encoding="UTF-8"?> |
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| 3 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.0//EN" "http://www.oasis-open.org/docbook/xml/4.0/docbookx.dtd"> |
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| 4 | |
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| 5 | <article> |
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| 6 | <title>The Hoard Memory Allocator</title> |
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| 7 | |
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| 8 | <articleinfo> |
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| 9 | <author> |
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| 10 | <firstname>Emery</firstname> |
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| 11 | <surname>Berger</surname> |
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| 12 | <affiliation>University of Massachusetts Amherst</affiliation> |
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| 13 | <street>Department of Computer Science</street> |
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| 14 | <city>Amherst</city> |
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| 15 | <state>Massachusetts</state> |
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| 16 | <country>USA</country> |
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| 17 | <email>emery@cs.umass.edu</email> |
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| 18 | </author> |
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| 19 | <pubdate>2004-12-08</pubdate> |
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| 20 | <revhistory> |
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| 21 | <revision> |
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| 22 | <revnumber>1.1</revnumber> |
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| 23 | <date>2004-12-08</date> |
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| 24 | <authorinitials>EDB</authorinitials> |
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| 25 | <revremark>Improved formatting</revremark> |
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| 26 | </revision> |
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| 27 | <revision> |
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| 28 | <revnumber>1.0</revnumber> |
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| 29 | <date>2004-12-06</date> |
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| 30 | <authorinitials>EDB</authorinitials> |
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| 31 | <revremark>First draft</revremark> |
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| 32 | </revision> |
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| 33 | </revhistory> |
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| 34 | <copyright> |
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| 35 | <year>2004</year> |
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| 36 | <holder role="mailto:emery@cs.umass.edu">Emery Berger</holder> |
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| 37 | </copyright> |
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| 38 | <abstract> |
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| 39 | Documentation for the Hoard scalable memory allocator, including build and usage directions for several platforms. |
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| 40 | </abstract> |
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| 41 | </articleinfo> |
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| 42 | |
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| 43 | <!-- |
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| 44 | add mailing list and website info. |
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| 45 | proper web links |
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| 46 | big line between sections |
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| 47 | |
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| 48 | --> |
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| 49 | |
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| 50 | <blockquote> |
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| 51 | <para> |
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| 52 | <emphasis role="strong">hoard:</emphasis> |
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| 53 | To amass and put away (anything valuable) for preservation, security, |
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| 54 | or future use; to treasure up: esp. money or wealth. |
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| 55 | </para> |
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| 56 | <para><emphasis>Oxford English Dictionary</emphasis> |
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| 57 | </para> |
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| 58 | </blockquote> |
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| 59 | |
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| 60 | <sect1 id="intro"> |
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| 61 | <title>Introduction</title> |
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| 62 | <para> |
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| 63 | The Hoard memory allocator is a fast, scalable, and memory-efficient |
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| 64 | memory allocator for shared-memory multiprocessors. It runs on a |
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| 65 | variety of platforms, including Linux, Solaris, and Windows. |
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| 66 | </para> |
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| 67 | <sect2> |
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| 68 | <title>Why Hoard?</title> |
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| 69 | <sect3> |
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| 70 | <title>Contention</title> |
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| 71 | <para> |
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| 72 | Multithreaded programs often do not scale because the heap is a |
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| 73 | bottleneck. When multiple threads simultaneously allocate or |
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| 74 | deallocate memory from the allocator, the allocator will serialize |
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| 75 | them. Programs making intensive use of the allocator actually slow |
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| 76 | down as the number of processors increases. Your program may be |
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| 77 | allocation-intensive without you realizing it, for instance, if your |
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| 78 | program makes many calls to the C++ Standard Template Library (STL). |
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| 79 | </para> |
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| 80 | </sect3> |
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| 81 | <sect3> |
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| 82 | <title>False Sharing</title> |
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| 83 | <para> |
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| 84 | The allocator can cause other problems for multithreaded code. It can |
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| 85 | lead to <emphasis>false sharing</emphasis> in your application: |
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| 86 | threads on different CPUs can end up with memory in the same cache |
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| 87 | line, or chunk of memory. Accessing these falsely-shared cache lines |
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| 88 | is hundreds of times slower than accessing unshared cache lines. |
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| 89 | </para> |
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| 90 | </sect3> |
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| 91 | <sect3> |
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| 92 | <title>Blowup</title> |
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| 93 | <para> |
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| 94 | Multithreaded programs can also lead the allocator to blowup memory |
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| 95 | consumption. This effect can multiply the amount of memory needed to |
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| 96 | run your application by the number of CPUs on your machine: four CPUs |
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| 97 | could mean that you need four times as much memory. Hoard is a fast |
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| 98 | allocator that solves all of these problems. |
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| 99 | </para> |
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| 100 | </sect3> |
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| 101 | </sect2> |
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| 102 | |
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| 103 | <sect2> |
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| 104 | <title>How Do I Use Hoard?</title> |
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| 105 | <para> |
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| 106 | Hoard is a drop-in replacement for malloc(), etc. In general, you just |
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| 107 | link it in or set just one environment variable. You do not have to |
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| 108 | change your source code in any way. See the section "Windows Builds" |
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| 109 | below for more information for particular platforms. |
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| 110 | </para> |
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| 111 | </sect2> |
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| 112 | |
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| 113 | <sect2> |
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| 114 | <title>Who's Using Hoard?</title> |
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| 115 | <para> |
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| 116 | Companies using Hoard in their products and servers include <ulink |
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| 117 | url="http://www.aol.com">AOL</ulink>, <ulink |
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| 118 | url="http://www.bt.com">British Telecom</ulink>, <ulink |
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| 119 | url="http://www.businessobjects.com">Business Objects</ulink> |
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| 120 | (formerly Crystal Decisions), <ulink |
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| 121 | url="http://www.entrust.com">Entrust</ulink>, <ulink |
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| 122 | url="http://www.novell.com">Novell</ulink>, <ulink |
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| 123 | url="http://www.openwave.com">OpenWave Systems</ulink> (for their |
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| 124 | Typhoon and Twister servers), and <ulink |
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| 125 | url="http://www.reuters.com">Reuters</ulink>. |
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| 126 | </para> |
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| 127 | |
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| 128 | <para> |
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| 129 | Open source projects using Hoard include the Bayonne GNU telephony |
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| 130 | server, the <ulink |
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| 131 | url="http://supertech.lcs.mit.edu/cilk/">Cilk</ulink> parallel |
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| 132 | programming language, the <ulink |
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| 133 | url="http://www.cs.dartmouth.edu/research/DaSSF/index.html">Dartmouth |
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| 134 | Scalable Simulation Framework</ulink>, and the <ulink |
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| 135 | url="http://www.gnu.org/software/commoncpp/">GNU Common C++</ulink> |
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| 136 | system. |
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| 137 | </para> |
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| 138 | </sect2> |
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| 139 | </sect1> |
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| 140 | |
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| 141 | <sect1 id="Building Hoard"> |
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| 142 | <title>Building Hoard</title> |
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| 143 | <para> |
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| 144 | You can use the available pre-built binaries or build Hoard |
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| 145 | yourself. Hoard is written to work on Windows and any variant of UNIX |
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| 146 | that supports threads, and should compile out of the box. Rather than |
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| 147 | using Makefiles or configure scripts, Hoard includes custom scripts |
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| 148 | that all start with the prefix compile. |
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| 149 | </para> |
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| 150 | |
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| 151 | <sect2> |
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| 152 | <title>Platform-specific directions</title> |
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| 153 | <sect2> |
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| 154 | <title>Linux and Solaris Builds</title> |
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| 155 | <para> |
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| 156 | You can compile Hoard out of the box for Linux and Solaris using the |
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| 157 | GNU compilers (g++) just by running the <filename>compile</filename> |
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| 158 | script: |
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| 159 | |
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| 160 | <programlisting> |
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| 161 | ./compile |
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| 162 | </programlisting> |
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| 163 | |
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| 164 | </para> |
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| 165 | </sect2> |
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| 166 | <sect2> |
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| 167 | <title>Windows Builds</title> |
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| 168 | <para> |
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| 169 | There are now three alternative ways of using Hoard with Windows. |
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| 170 | |
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| 171 | <itemizedlist> |
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| 172 | |
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| 173 | <listitem> |
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| 174 | <para> |
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| 175 | The first approach builds a DLL, <filename>libhoard.dll</filename> and |
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| 176 | its associated library <filename>libhoard.lib</filename>. |
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| 177 | |
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| 178 | <programlisting> |
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| 179 | .\compile-dll |
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| 180 | </programlisting> |
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| 181 | </para> |
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| 182 | </listitem> |
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| 183 | |
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| 184 | <listitem> |
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| 185 | <para> |
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| 186 | The second approach relies on Microsoft Research's <ulink |
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| 187 | url="http://research.microsoft.com/sn/detours">Detours</ulink>. With |
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| 188 | Detours, you can take advantage of Hoard without having to relink your |
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| 189 | applications. Install Detours into <filename |
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| 190 | class="directory">C:\detours</filename>, and then build the Hoard |
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| 191 | detours library: |
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| 192 | |
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| 193 | <programlisting> |
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| 194 | .\compile-detours |
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| 195 | </programlisting> |
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| 196 | </para> |
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| 197 | </listitem> |
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| 198 | |
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| 199 | <listitem> |
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| 200 | <para> |
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| 201 | The third approach generates winhoard, which replaces malloc/new calls |
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| 202 | in your program <emphasis>and</emphasis> in any DLLs it might use. |
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| 203 | |
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| 204 | <programlisting> |
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| 205 | .\compile-winhoard |
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| 206 | </programlisting> |
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| 207 | </para> |
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| 208 | </listitem> |
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| 209 | </itemizedlist> |
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| 210 | </para> |
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| 211 | </sect2> |
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| 212 | </sect2> |
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| 213 | </sect1> |
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| 214 | |
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| 215 | |
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| 216 | <sect1 id="Using Hoard"> |
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| 217 | <title>Using Hoard</title> |
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| 218 | <sect2> |
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| 219 | <title>UNIX</title> |
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| 220 | <para> |
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| 221 | In UNIX, you can use the <envar>LD_PRELOAD</envar> variable to use |
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| 222 | Hoard instead of the system allocator for any program not linked with |
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| 223 | the "static option" (that's most programs). Below are settings for |
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| 224 | Linux and Solaris. |
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| 225 | </para> |
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| 226 | <sect3> |
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| 227 | <title>Linux</title> |
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| 228 | <para> |
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| 229 | <programlisting> |
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| 230 | LD_PRELOAD="/path/libhoard.so:/usr/lib/libdl.so" |
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| 231 | </programlisting> |
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| 232 | </para> |
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| 233 | </sect3> |
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| 234 | <sect3> |
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| 235 | <title>Solaris</title> |
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| 236 | <para> |
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| 237 | Depending on whether you are using the GNU-compiled version (as |
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| 238 | produced by <filename>compile</filename>) or the Sun |
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| 239 | Workshop-compiled versions (produced by |
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| 240 | <filename>compile-sunw</filename>), your settings will be slightly |
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| 241 | different. |
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| 242 | </para> |
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| 243 | |
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| 244 | <informaltable frame="none"> |
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| 245 | <tgroup cols="2"> |
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| 246 | <colspec colwidth="1in"/> |
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| 247 | <thead> |
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| 248 | <row> |
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| 249 | <entry>Version</entry> |
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| 250 | <entry>Setting</entry> |
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| 251 | </row> |
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| 252 | </thead> |
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| 253 | <tbody> |
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| 254 | <row valign="center"> |
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| 255 | <entry>GNU-compiled</entry> |
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| 256 | <entry> |
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| 257 | <programlisting> |
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| 258 | LD_PRELOAD="/path/libhoard.so:/usr/lib/libdl.so" |
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| 259 | </programlisting> |
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| 260 | </entry> |
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| 261 | </row> |
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| 262 | <row valign="center"> |
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| 263 | <entry>Sun-compiled (<emphasis>32-bits</emphasis>)</entry> |
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| 264 | <entry> |
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| 265 | <programlisting> |
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| 266 | LD_PRELOAD="/path/libhoard_32.so" |
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| 267 | </programlisting> |
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| 268 | </entry> |
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| 269 | </row> |
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| 270 | <row valign="center"> |
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| 271 | <entry>Sun-compiled (<emphasis>64-bits</emphasis>)</entry> |
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| 272 | <entry> |
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| 273 | <programlisting> |
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| 274 | LD_PRELOAD="/path/libhoard_64.so:/usr/lib/64/libCrun.so.1:/usr/lib/64/libdl.so" |
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| 275 | </programlisting> |
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| 276 | </entry> |
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| 277 | </row> |
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| 278 | </tbody> |
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| 279 | </tgroup> |
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| 280 | </informaltable> |
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| 281 | <note> |
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| 282 | <para> |
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| 283 | For some security-sensitive applications, Solaris requires you place |
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| 284 | libraries used in <envar>LD_PRELOAD</envar> into the <filename |
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| 285 | class="directory">/usr/lib/secure</filename> directory. In that event, |
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| 286 | after copying these libraries into <filename |
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| 287 | class="directory">/usr/lib/secure</filename>, set |
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| 288 | <envar>LD_PRELOAD</envar> by omitting the absolute locations of the libraries, as follows: |
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| 289 | <programlisting> |
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| 290 | LD_PRELOAD="libhoard.so:libCrun.so.1:libdl.so" |
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| 291 | </programlisting> |
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| 292 | </para> |
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| 293 | </note> |
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| 294 | |
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| 295 | </sect3> |
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| 296 | </sect2> |
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| 297 | |
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| 298 | <sect2> |
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| 299 | <title>Windows</title> |
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| 300 | <para> |
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| 301 | There are three ways to use Hoard on Windows. |
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| 302 | </para> |
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| 303 | <orderedlist> |
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| 304 | <listitem> |
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| 305 | Using Detours |
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| 306 | <para> |
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| 307 | By using Detours, you can take advantage of Hoard's benefits without |
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| 308 | relinking your Windows application (as long as it is dynamically |
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| 309 | linked to the C runtime libraries). You will need to use one of the |
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| 310 | two included Detours tools (<filename>setdll.exe</filename> or |
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| 311 | <filename>withdll.exe</filename> in the <filename |
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| 312 | class="directory">detours/</filename> directory) in conjunction with |
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| 313 | this version of Hoard. To <emphasis>temporarily</emphasis> use Hoard |
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| 314 | as the allocator for a given application, use <filename>withdll</filename>: |
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| 315 | |
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| 316 | <programlisting> |
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| 317 | withdll -d:hoarddetours.dll myprogram.exe |
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| 318 | </programlisting> |
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| 319 | |
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| 320 | If you want your program to use Hoard without having to invoke |
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| 321 | <filename>withdll</filename> every time, you can use |
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| 322 | <filename>setdll</filename> to add it to your executable: |
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| 323 | |
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| 324 | <programlisting> |
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| 325 | setdll -d:hoarddetours.dll myprogram.exe myprogram.exe |
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| 326 | </programlisting> |
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| 327 | |
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| 328 | You can later remove Hoard from your executable as follows: |
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| 329 | |
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| 330 | <programlisting> |
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| 331 | setdll -r:hoarddetours.dll myprogram.exe |
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| 332 | </programlisting> |
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| 333 | </para> |
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| 334 | </listitem> |
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| 335 | <listitem> |
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| 336 | Using <filename>winhoard</filename> |
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| 337 | <para> |
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| 338 | Another method is to use <filename>winhoard</filename>. Winhoard, |
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| 339 | like Detours, replaces malloc/new calls from your program and any DLLs |
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| 340 | it might use (leaving <filename>HeapAlloc</filename> calls |
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| 341 | intact). One advantage is that it does not require Detours to do this. |
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| 342 | |
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| 343 | To use the Winhoard version, link your executable with |
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| 344 | <filename>usewinhoard.obj</filename> and |
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| 345 | <filename>winhoard.lib</filename>, and then use |
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| 346 | <filename>winhoard.dll</filename>: |
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| 347 | |
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| 348 | <programlisting> |
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| 349 | cl /Ox /MD /c usewinhoard.cpp |
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| 350 | cl /Ox /MD myprogram.cpp usewinhoard.obj winhoard.lib |
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| 351 | </programlisting> |
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| 352 | |
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| 353 | </para> |
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| 354 | </listitem> |
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| 355 | <listitem> |
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| 356 | Using <filename>libhoard</filename> |
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| 357 | <para> |
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| 358 | |
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| 359 | The last method is to link directly with the |
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| 360 | <filename>libhoard</filename> DLL. This approach is simple, but only |
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| 361 | suitable for small applications, since it will not affect malloc calls |
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| 362 | in any other DLL you might load. To use this option, you should put |
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| 363 | the following into your source code as the very first lines: |
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| 364 | |
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| 365 | <programlisting> |
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| 366 | #if defined(USE_HOARD) |
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| 367 | #pragma comment(lib, "libhoard.lib") |
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| 368 | #endif |
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| 369 | </programlisting> |
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| 370 | |
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| 371 | This stanza should be in the first part of a header file included by |
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| 372 | all of your code. It ensures that Hoard loads before any other library |
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| 373 | (you will need <filename>libhoard.lib</filename> in your path). When |
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| 374 | you execute your program, as long as <filename>libhoard.dll</filename> |
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| 375 | is in your path, your program will run with Hoard instead of the |
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| 376 | system allocator. Note that you must compile your program with the |
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| 377 | <filename>/MD</filename> flag, as in: |
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| 378 | |
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| 379 | <programlisting> |
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| 380 | cl /MD /G6 /Ox /DUSE_HOARD=1 myprogram.cpp |
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| 381 | </programlisting> |
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| 382 | |
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| 383 | Hoard will not work if you use another switch (like |
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| 384 | <filename>/MT</filename>) to compile your program. |
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| 385 | </para> |
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| 386 | </listitem> |
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| 387 | </orderedlist> |
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| 388 | </sect2> |
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| 389 | </sect1> |
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| 390 | |
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| 391 | |
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| 392 | <sect1 id="FAQs"> |
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| 393 | <title>Frequently Asked Questions</title> |
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| 394 | <qandaset> |
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| 395 | |
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| 396 | <qandaentry> |
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| 397 | <question> |
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| 398 | <para>What kind of applications will Hoard speed up?</para> |
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| 399 | </question> |
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| 400 | <answer> |
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| 401 | <para> |
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| 402 | Hoard will always improve the performance of multithreaded programs |
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| 403 | running on multiprocessors that make frequent use of the heap (calls |
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| 404 | to malloc/free or new/delete, as well as many STL functions). Because |
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| 405 | Hoard avoids false sharing, Hoard also speeds up programs that only |
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| 406 | occasionally call heap functions but access these objects frequently. |
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| 407 | </para> |
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| 408 | </answer> |
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| 409 | </qandaentry> |
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| 410 | |
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| 411 | <qandaentry> |
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| 412 | <question> |
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| 413 | <para>I'm using the STL but not seeing any performance improvement. Why not?</para> |
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| 414 | </question> |
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| 415 | <answer> |
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| 416 | <para> |
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| 417 | In order to benefit from Hoard, you have to tell STL to use malloc instead of its internal custom memory allocator, as in: |
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| 418 | |
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| 419 | <programlisting> |
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| 420 | typedef list<unsigned int, malloc_alloc> mylist; |
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| 421 | </programlisting> |
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| 422 | |
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| 423 | </para> |
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| 424 | </answer> |
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| 425 | </qandaentry> |
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| 426 | |
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| 427 | |
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| 428 | <qandaentry> |
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| 429 | <question> |
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| 430 | <para> Have you compared Hoard against mtmalloc or libumem?</para> |
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| 431 | </question> |
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| 432 | <answer> |
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| 433 | <para> |
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| 434 | Yes. Hoard is much faster than either. For example, here's an |
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| 435 | execution of threadtest on Solaris: |
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| 436 | |
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| 437 | <informaltable frame="none"> |
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| 438 | <tgroup cols="2"> |
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| 439 | <tbody> |
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| 440 | <row> |
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| 441 | <entry>Default:</entry> |
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| 442 | <entry>4.60 seconds</entry> |
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| 443 | </row> |
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| 444 | <row> |
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| 445 | <entry>Libmtmalloc:</entry> |
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| 446 | <entry>6.23 seconds</entry> |
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| 447 | </row> |
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| 448 | <row> |
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| 449 | <entry>Libumem:</entry> |
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| 450 | <entry>5.47 seconds</entry> |
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| 451 | </row> |
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| 452 | <row> |
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| 453 | <entry>Hoard 3.2:</entry> |
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| 454 | <entry>1.99 seconds</entry> |
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| 455 | </row> |
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| 456 | </tbody> |
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| 457 | </tgroup> |
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| 458 | </informaltable> |
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| 459 | </para> |
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| 460 | </answer> |
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| 461 | </qandaentry> |
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| 462 | |
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| 463 | <qandaentry> |
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| 464 | <question> |
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| 465 | <para> |
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| 466 | What systems does Hoard work on? |
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| 467 | </para> |
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| 468 | </question> |
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| 469 | <answer> |
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| 470 | <para> |
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| 471 | Hoard has been successfully tested on numerous Windows, Linux and |
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| 472 | Solaris systems, including a 4-processor x86 box running Windows |
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| 473 | NT/2000, a 4-processor x86 box running RedHat Linux 6.0 and 6.1, and a |
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| 474 | 16-processor Sun Enterprise server running Solaris. |
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| 475 | </para> |
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| 476 | </answer> |
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| 477 | </qandaentry> |
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| 478 | |
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| 479 | <qandaentry> |
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| 480 | <question> |
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| 481 | <para> |
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| 482 | Have you compared Hoard with SmartHeap SMP? |
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| 483 | </para> |
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| 484 | </question> |
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| 485 | <answer> |
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| 486 | <para> |
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| 487 | We tried SmartHeap SMP but it did not work on our Suns (due to an |
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| 488 | apparent race condition in the code). |
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| 489 | </para> |
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| 490 | </answer> |
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| 491 | </qandaentry> |
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| 492 | </qandaset> |
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| 493 | </sect1> |
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| 494 | |
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| 495 | <sect1 id="More Info"> |
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| 496 | <title>More Information</title> |
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| 497 | <para> |
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| 498 | The first place to look for Hoard-related information is at the Hoard |
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| 499 | web page, <ulink url="http://www.hoard.org">www.hoard.org</ulink>. |
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| 500 | </para> |
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| 501 | |
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| 502 | <para> |
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| 503 | There are two mailing lists you should consider being on if you are a |
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| 504 | user of Hoard. If you are just interested in being informed of new |
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| 505 | releases, join the <ulink |
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| 506 | url="http://groups.yahoo.com/group/hoard-announce/">Hoard-Announce</ulink> |
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| 507 | list. For general Hoard discussion, join the <ulink |
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| 508 | url="http://groups.yahoo.com/group/hoard/">Hoard</ulink> mailing |
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| 509 | list. You can also search the archives of these lists. |
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| 510 | </para> |
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| 511 | </sect1> |
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| 512 | |
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| 513 | <sect1 id="License Info"> |
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| 514 | <title>License Information</title> |
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| 515 | |
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| 516 | <para> |
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| 517 | The use and distribution of Hoard is governed by the GNU General |
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| 518 | Public License as published by the <ulink |
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| 519 | url="http://www.fsf.org">Free Software Foundation</ulink>: see the |
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| 520 | included file <filename>COPYING</filename> for more details. |
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| 521 | </para> |
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| 522 | |
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| 523 | <para> |
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| 524 | Because of the restrictions imposed by this license, most commercial |
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| 525 | users of Hoard have purchased commercial licenses, which are arranged |
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| 526 | through the University of Texas at Austin. <ulink |
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| 527 | url="mailto:software@otc.utexas.edu">Contact Richard Friedman</ulink> |
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| 528 | at the Office of Technology Commercialization at The University of |
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| 529 | Texas at Austin for more information (phone: (512) 471-4738). |
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| 530 | </para> |
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| 531 | |
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| 532 | </sect1> |
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| 533 | |
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| 534 | </article> |
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