1<?xml version="1.0" encoding="ISO-8859-1"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- 4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 5 This file is generated from xml source: DO NOT EDIT 6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 7 --> 8<title>Multi-Processing Modules (MPMs) - Apache HTTP Server</title> 9<link href="./style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> 10<link href="./style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> 11<link href="./style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="./style/css/prettify.css" /> 12<script src="./style/scripts/prettify.js" type="text/javascript"> 13</script> 14 15<link href="./images/favicon.ico" rel="shortcut icon" /></head> 16<body id="manual-page"><div id="page-header"> 17<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p> 18<p class="apache">Apache HTTP Server Version 2.4</p> 19<img alt="" src="./images/feather.gif" /></div> 20<div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div> 21<div id="path"> 22<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="./">Version 2.4</a></div><div id="page-content"><div id="preamble"><h1>Multi-Processing Modules (MPMs)</h1> 23<div class="toplang"> 24<p><span>Available Languages: </span><a href="./de/mpm.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | 25<a href="./en/mpm.html" title="English"> en </a> | 26<a href="./es/mpm.html" hreflang="es" rel="alternate" title="Espa�ol"> es </a> | 27<a href="./fr/mpm.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a> | 28<a href="./ja/mpm.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | 29<a href="./ko/mpm.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> | 30<a href="./tr/mpm.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a> | 31<a href="./zh-cn/mpm.html" hreflang="zh-cn" rel="alternate" title="Simplified Chinese"> zh-cn </a></p> 32</div> 33 34<p>This document describes what a Multi-Processing Module is and 35how they are used by the Apache HTTP Server.</p> 36</div> 37<div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#introduction">Introduction</a></li> 38<li><img alt="" src="./images/down.gif" /> <a href="#defaults">MPM Defaults</a></li> 39<li><img alt="" src="./images/down.gif" /> <a href="#static">Building an MPM as a static module</a></li> 40<li><img alt="" src="./images/down.gif" /> <a href="#dynamic">Building an MPM as a DSO module</a></li> 41</ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 42<div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> 43<div class="section"> 44<h2><a name="introduction" id="introduction">Introduction</a></h2> 45 46 <p>The Apache HTTP Server is designed to be a powerful and 47 flexible web server that can work on a very wide variety of 48 platforms in a range of different environments. Different 49 platforms and different environments often require different 50 features, or may have different ways of implementing the same 51 feature most efficiently. Apache httpd has always accommodated a wide 52 variety of environments through its modular design. This design 53 allows the webmaster to choose which features will be included 54 in the server by selecting which modules to load either at 55 compile-time or at run-time.</p> 56 57 <p>Apache HTTP Server 2.0 extends this modular design to the most basic 58 functions of a web server. The server ships with a selection of 59 Multi-Processing Modules (MPMs) which are responsible for 60 binding to network ports on the machine, accepting requests, 61 and dispatching children to handle the requests.</p> 62 63 <p>Extending the modular design to this level of the server 64 allows two important benefits:</p> 65 66 <ul> 67 <li>Apache httpd can more cleanly and efficiently support a wide 68 variety of operating systems. In particular, the Windows 69 version of the server is now much more efficient, since 70 <code class="module"><a href="./mod/mpm_winnt.html">mpm_winnt</a></code> can use native 71 networking features in place of the POSIX layer used in 72 Apache httpd 1.3. This benefit also extends to other operating 73 systems that implement specialized MPMs.</li> 74 75 <li>The server can be better customized for the needs of the 76 particular site. For example, sites that need a great deal of 77 scalability can choose to use a threaded MPM like 78 <code class="module"><a href="./mod/worker.html">worker</a></code> or <code class="module"><a href="./mod/event.html">event</a></code>, while sites requiring 79 stability or compatibility with older software can use a 80 <code class="module"><a href="./mod/prefork.html">prefork</a></code>.</li> 81 </ul> 82 83 <p>At the user level, MPMs appear much like other Apache httpd 84 modules. The main difference is that one and only one MPM must 85 be loaded into the server at any time. The list of available 86 MPMs appears on the <a href="mod/">module index page</a>.</p> 87 88</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> 89<div class="section"> 90<h2><a name="defaults" id="defaults">MPM Defaults</a></h2> 91 92<p>The following table lists the default MPMs for various operating 93systems. This will be the MPM selected if you do not make another 94choice at compile-time.</p> 95 96<table class="bordered"><tr><td>Netware</td><td><code class="module"><a href="./mod/mpm_netware.html">mpm_netware</a></code></td></tr> 97<tr class="odd"><td>OS/2</td><td><code class="module"><a href="./mod/mpmt_os2.html">mpmt_os2</a></code></td></tr> 98<tr><td>Unix</td><td><code class="module"><a href="./mod/prefork.html">prefork</a></code>, <code class="module"><a href="./mod/worker.html">worker</a></code>, or 99 <code class="module"><a href="./mod/event.html">event</a></code>, depending on platform capabilities</td></tr> 100<tr class="odd"><td>Windows</td><td><code class="module"><a href="./mod/mpm_winnt.html">mpm_winnt</a></code></td></tr> 101</table> 102 103<div class="note"><p>Here, 'Unix' is used to mean Unix-like operating systems, such as 104Linux, BSD, Solaris, Mac OS X, etc.</p></div> 105 106<p>In the case of Unix, the decision as to which MPM is installed is 107based on two questions:</p> 108<p>1. Does the system support threads?</p> 109<p>2. Does the system support thread-safe polling (Specifically, the 110kqueue and epoll functions)?</p> 111 112<p>If the answer to both questions is 'yes', the default MPM is 113<code class="module"><a href="./mod/event.html">event</a></code>.</p> 114 115<p>If The answer to #1 is 'yes', but the answer to #2 is 'no', the 116default will be <code class="module"><a href="./mod/worker.html">worker</a></code>.</p> 117 118<p>If the answer to both questions is 'no', then the default MPM will be 119<code class="module"><a href="./mod/prefork.html">prefork</a></code>.</p> 120 121<p>In practical terms, this means that the default will almost always be 122<code class="module"><a href="./mod/event.html">event</a></code>, as all modern operating systems support these 123two features.</p> 124 125</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> 126<div class="section"> 127<h2><a name="static" id="static">Building an MPM as a static module</a></h2> 128 129 <p>MPMs can be built as static modules on all platforms. A single MPM 130 is chosen at build time and linked into the server. The server must 131 be rebuilt in order to change the MPM.</p> 132 133 <p>To override the default MPM choice, use the 134 <code>--with-mpm=<em>NAME</em></code> option of the 135 <code class="program"><a href="./programs/configure.html">configure</a></code> script. <em>NAME</em> is the name of the 136 desired MPM.</p> 137 138 <p>Once the server has been compiled, it is possible to determine which MPM 139 was chosen by using <code>./httpd -l</code>. This command will list every 140 module that is compiled into the server, including the MPM.</p> 141 142</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> 143<div class="section"> 144<h2><a name="dynamic" id="dynamic">Building an MPM as a DSO module</a></h2> 145 146 <p>On Unix and similar platforms, MPMs can be built as DSO modules and 147 dynamically loaded into the server in the same manner as other DSO 148 modules. Building MPMs as DSO modules allows the MPM to be changed by 149 updating the <code class="directive"><a href="./mod/mod_so.html#loadmodule">LoadModule</a></code> directive 150 for the MPM instead of by rebuilding the server.</p> 151 152 <p>This feature is enabled using the 153 <code>--enable-mpms-shared</code> option of the <code class="program"><a href="./programs/configure.html">configure</a></code> 154 script. 155 With argument <code><em>all</em></code>, all possible MPMs for the platform 156 will be installed. Alternately, a list of MPMs can be specified as the 157 argument.</p> 158 159 <p>The default MPM, either selected automatically or specified with the 160 <code>--with-mpm</code> option of the <code class="program"><a href="./programs/configure.html">configure</a></code> 161 script, will be loaded in the generated server configuration file. Edit the 162 <code class="directive"><a href="./mod/mod_so.html#loadmodule">LoadModule</a></code> directive to select a 163 different MPM.</p> 164 165</div></div> 166<div class="bottomlang"> 167<p><span>Available Languages: </span><a href="./de/mpm.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | 168<a href="./en/mpm.html" title="English"> en </a> | 169<a href="./es/mpm.html" hreflang="es" rel="alternate" title="Espa�ol"> es </a> | 170<a href="./fr/mpm.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a> | 171<a href="./ja/mpm.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | 172<a href="./ko/mpm.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> | 173<a href="./tr/mpm.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a> | 174<a href="./zh-cn/mpm.html" hreflang="zh-cn" rel="alternate" title="Simplified Chinese"> zh-cn </a></p> 175</div><div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div> 176<script type="text/javascript"><!--//--><![CDATA[//><!-- 177var comments_shortname = 'httpd'; 178var comments_identifier = 'http://httpd.apache.org/docs/2.4/mpm.html'; 179(function(w, d) { 180 if (w.location.hostname.toLowerCase() == "httpd.apache.org") { 181 d.write('<div id="comments_thread"><\/div>'); 182 var s = d.createElement('script'); 183 s.type = 'text/javascript'; 184 s.async = true; 185 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; 186 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); 187 } 188 else { 189 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); 190 } 191})(window, document); 192//--><!]]></script></div><div id="footer"> 193<p class="apache">Copyright 2013 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> 194<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- 195if (typeof(prettyPrint) !== 'undefined') { 196 prettyPrint(); 197} 198//--><!]]></script> 199</body></html>
