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diff --git a/libstdc++-v3/doc/html/manual/ext_allocators.html b/libstdc++-v3/doc/html/manual/ext_allocators.html index 37bed0b14f7..bd283b75c40 100644 --- a/libstdc++-v3/doc/html/manual/ext_allocators.html +++ b/libstdc++-v3/doc/html/manual/ext_allocators.html @@ -1,10 +1,10 @@ <?xml version="1.0" encoding="UTF-8" standalone="no"?> -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 20. Allocators</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><meta name="keywords" content=" ISO C++ , library " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="extensions.html" title="Part III. Extensions" /><link rel="prev" href="bk01pt03ch19s07.html" title="Diagnostics" /><link rel="next" href="bitmap_allocator.html" title="bitmap_allocator" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 20. Allocators</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="bk01pt03ch19s07.html">Prev</a> </td><th width="60%" align="center">Part III. +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Chapter 20. Allocators</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" ISO C++ , library "/><link rel="home" href="../spine.html" title="The GNU C++ Library"/><link rel="up" href="extensions.html" title="Part III. Extensions"/><link rel="prev" href="bk01pt03ch19s07.html" title="Diagnostics"/><link rel="next" href="bitmap_allocator.html" title="bitmap_allocator"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 20. Allocators</th></tr><tr><td align="left"><a accesskey="p" href="bk01pt03ch19s07.html">Prev</a> </td><th width="60%" align="center">Part III. Extensions -</th><td width="20%" align="right"> <a accesskey="n" href="bitmap_allocator.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 20. Allocators"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.allocator"></a>Chapter 20. Allocators</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="ext_allocators.html#manual.ext.allocator.mt">mt_allocator</a></span></dt><dd><dl><dt><span class="sect2"><a href="ext_allocators.html#allocator.mt.intro">Intro</a></span></dt><dt><span class="sect2"><a href="ext_allocators.html#allocator.mt.design_issues">Design Issues</a></span></dt><dt><span class="sect2"><a href="ext_allocators.html#allocator.mt.impl">Implementation</a></span></dt><dt><span class="sect2"><a href="ext_allocators.html#allocator.mt.example_single">Single Thread Example</a></span></dt><dt><span class="sect2"><a href="ext_allocators.html#allocator.mt.example_multi">Multiple Thread Example</a></span></dt></dl></dd><dt><span class="sect1"><a href="bitmap_allocator.html">bitmap_allocator</a></span></dt><dd><dl><dt><span class="sect2"><a href="bitmap_allocator.html#allocator.bitmap.design">Design</a></span></dt><dt><span class="sect2"><a href="bitmap_allocator.html#allocator.bitmap.impl">Implementation</a></span></dt></dl></dd></dl></div><div class="sect1" title="mt_allocator"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.ext.allocator.mt"></a>mt_allocator</h2></div></div></div><p> -</p><div class="sect2" title="Intro"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.intro"></a>Intro</h3></div></div></div><p> +</th><td align="right"> <a accesskey="n" href="bitmap_allocator.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 20. Allocators"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.allocator"/>Chapter 20. Allocators</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="ext_allocators.html#manual.ext.allocator.mt">mt_allocator</a></span></dt><dd><dl><dt><span class="section"><a href="ext_allocators.html#allocator.mt.intro">Intro</a></span></dt><dt><span class="section"><a href="ext_allocators.html#allocator.mt.design_issues">Design Issues</a></span></dt><dt><span class="section"><a href="ext_allocators.html#allocator.mt.impl">Implementation</a></span></dt><dt><span class="section"><a href="ext_allocators.html#allocator.mt.example_single">Single Thread Example</a></span></dt><dt><span class="section"><a href="ext_allocators.html#allocator.mt.example_multi">Multiple Thread Example</a></span></dt></dl></dd><dt><span class="section"><a href="bitmap_allocator.html">bitmap_allocator</a></span></dt><dd><dl><dt><span class="section"><a href="bitmap_allocator.html#allocator.bitmap.design">Design</a></span></dt><dt><span class="section"><a href="bitmap_allocator.html#allocator.bitmap.impl">Implementation</a></span></dt></dl></dd></dl></div><div class="section" title="mt_allocator"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.allocator.mt"/>mt_allocator</h2></div></div></div><p> +</p><div class="section" title="Intro"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.intro"/>Intro</h3></div></div></div><p> The mt allocator [hereinafter referred to simply as "the allocator"] is a fixed size (power of two) allocator that was initially developed specifically to suit the needs of multi threaded @@ -20,7 +20,7 @@ </p><p> The aim of this document is to describe - from an application point of view - the "inner workings" of the allocator. -</p></div><div class="sect2" title="Design Issues"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.design_issues"></a>Design Issues</h3></div></div></div><div class="sect3" title="Overview"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.overview"></a>Overview</h4></div></div></div><p> There are three general components to the allocator: a datum +</p></div><div class="section" title="Design Issues"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.design_issues"/>Design Issues</h3></div></div></div><div class="section" title="Overview"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.overview"/>Overview</h4></div></div></div><p> There are three general components to the allocator: a datum describing the characteristics of the memory pool, a policy class containing this pool that links instantiation types to common or individual pools, and a class inheriting from the policy class that is @@ -56,10 +56,10 @@ tuning, for instance. </pre><p> This class has the interface required for standard library allocator classes, namely member functions <code class="code">allocate</code> and <code class="code">deallocate</code>, plus others. -</p></div></div><div class="sect2" title="Implementation"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.impl"></a>Implementation</h3></div></div></div><div class="sect3" title="Tunable Parameters"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.tune"></a>Tunable Parameters</h4></div></div></div><p>Certain allocation parameters can be modified, or tuned. There +</p></div></div><div class="section" title="Implementation"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.impl"/>Implementation</h3></div></div></div><div class="section" title="Tunable Parameters"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.tune"/>Tunable Parameters</h4></div></div></div><p>Certain allocation parameters can be modified, or tuned. There exists a nested <code class="code">struct __pool_base::_Tune</code> that contains all these parameters, which include settings for -</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Alignment</p></li><li class="listitem"><p>Maximum bytes before calling <code class="code">::operator new</code> directly</p></li><li class="listitem"><p>Minimum bytes</p></li><li class="listitem"><p>Size of underlying global allocations</p></li><li class="listitem"><p>Maximum number of supported threads</p></li><li class="listitem"><p>Migration of deallocations to the global free list</p></li><li class="listitem"><p>Shunt for global <code class="code">new</code> and <code class="code">delete</code></p></li></ul></div><p>Adjusting parameters for a given instance of an allocator can only +</p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p>Alignment</p></li><li class="listitem"><p>Maximum bytes before calling <code class="code">::operator new</code> directly</p></li><li class="listitem"><p>Minimum bytes</p></li><li class="listitem"><p>Size of underlying global allocations</p></li><li class="listitem"><p>Maximum number of supported threads</p></li><li class="listitem"><p>Migration of deallocations to the global free list</p></li><li class="listitem"><p>Shunt for global <code class="code">new</code> and <code class="code">delete</code></p></li></ul></div><p>Adjusting parameters for a given instance of an allocator can only happen before any allocations take place, when the allocator itself is initialized. For instance: </p><pre class="programlisting"> @@ -95,7 +95,7 @@ int main() return 0; } -</pre></div><div class="sect3" title="Initialization"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.init"></a>Initialization</h4></div></div></div><p> +</pre></div><div class="section" title="Initialization"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.init"/>Initialization</h4></div></div></div><p> The static variables (pointers to freelists, tuning parameters etc) are initialized as above, or are set to the global defaults. </p><p> @@ -187,7 +187,7 @@ The _S_initialize() function: for this specific bin. This only occurs when a number of blocks are grabbed from the global list to a thread specific list or when a thread decides to return some blocks to the global freelist. -</p></div><div class="sect3" title="Deallocation Notes"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.deallocation"></a>Deallocation Notes</h4></div></div></div><p> Notes about deallocation. This allocator does not explicitly +</p></div><div class="section" title="Deallocation Notes"><div class="titlepage"><div><div><h4 class="title"><a id="allocator.mt.deallocation"/>Deallocation Notes</h4></div></div></div><p> Notes about deallocation. This allocator does not explicitly release memory. Because of this, memory debugging programs like valgrind or purify may notice leaks: sorry about this inconvenience. Operating systems will reclaim allocated memory at @@ -212,9 +212,9 @@ containers, this works, as an instance of the allocator is constructed as part of a container's constructor. However, this assumption is implementation-specific, and subject to change. For an example of a pool that frees memory, see the following - <a class="ulink" href="http://gcc.gnu.org/viewcvs/trunk/libstdc++-v3/testsuite/ext/mt_allocator/deallocate_local-6.cc?view=markup" target="_top"> + <a class="link" href="http://gcc.gnu.org/viewcvs/trunk/libstdc++-v3/testsuite/ext/mt_allocator/deallocate_local-6.cc?view=markup"> example.</a> -</p></div></div><div class="sect2" title="Single Thread Example"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.example_single"></a>Single Thread Example</h3></div></div></div><p> +</p></div></div><div class="section" title="Single Thread Example"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.example_single"/>Single Thread Example</h3></div></div></div><p> Let's start by describing how the data on a freelist is laid out in memory. This is the first two blocks in freelist for thread id 3 in bin 3 (8 bytes): </p><pre class="programlisting"> @@ -290,7 +290,7 @@ of the global freelist and update the pointer as needed The decision to add deallocated blocks to the front of the freelist was made after a set of performance measurements that showed that this is roughly 10% faster than maintaining a set of "last pointers" as well. -</p></div><div class="sect2" title="Multiple Thread Example"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.example_multi"></a>Multiple Thread Example</h3></div></div></div><p> +</p></div><div class="section" title="Multiple Thread Example"><div class="titlepage"><div><div><h3 class="title"><a id="allocator.mt.example_multi"/>Multiple Thread Example</h3></div></div></div><p> In the ST example we never used the thread_id variable present in each block. Let's start by explaining the purpose of this in a MT application. </p><p> @@ -394,4 +394,4 @@ mutex to be locked) this operation is also made in chunks of blocks a threads freelist mentioned above). The "formula" used can probably be improved to further reduce the risk of blocks being "bounced back and forth" between freelists. -</p></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="bk01pt03ch19s07.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="extensions.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="bitmap_allocator.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Diagnostics </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> bitmap_allocator</td></tr></table></div></body></html> +</p></div></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td align="left"><a accesskey="p" href="bk01pt03ch19s07.html">Prev</a> </td><td align="center"><a accesskey="u" href="extensions.html">Up</a></td><td align="right"> <a accesskey="n" href="bitmap_allocator.html">Next</a></td></tr><tr><td align="left" valign="top">Diagnostics </td><td align="center"><a accesskey="h" href="../spine.html">Home</a></td><td align="right" valign="top"> bitmap_allocator</td></tr></table></div></body></html> |
