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>event - 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> 17<div id="page-header"> 18<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> 19<p class="apache">Apache HTTP Server Version 2.2</p> 20<img alt="" src="/images/feather.gif" /></div> 21<div class="up"><a href="./"><img title="<-" alt="<-" src="/images/left.gif" /></a></div> 22<div id="path"> 23<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 2.2</a> > <a href="./">Modules</a></div> 24<div id="page-content"> 25<div id="preamble"><h1>Apache MPM event</h1> 26<div class="toplang"> 27<p><span>Available Languages: </span><a href="/en/mod/event.html" title="English"> en </a></p> 28</div> 29<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>An experimental variant of the standard <code class="module"><a href="/mod/worker.html">worker</a></code> 30MPM</td></tr> 31<tr><th><a href="module-dict.html#Status">Status:</a></th><td>MPM</td></tr> 32<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>mpm_event_module</td></tr> 33<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>event.c</td></tr></table> 34<h3>Summary</h3> 35 36 <div class="warning"><h3>Warning</h3> 37 <p>This MPM is experimental, so it may or may not work as 38 expected.</p> 39 </div> 40 41 <p>The <code class="module"><a href="/mod/event.html">event</a></code> Multi-Processing Module (MPM) is 42 designed to allow more requests to be served simultaneously by 43 passing off some processing work to supporting threads, freeing up 44 the main threads to work on new requests. It is based on the 45 <code class="module"><a href="/mod/worker.html">worker</a></code> MPM, which implements a hybrid 46 multi-process multi-threaded server. Run-time configuration 47 directives are identical to those provided by 48 <code class="module"><a href="/mod/worker.html">worker</a></code>.</p> 49 50 <p>To use the <code class="module"><a href="/mod/event.html">event</a></code> MPM, add 51 <code>--with-mpm=event</code> to the <code class="program"><a href="/programs/configure.html">configure</a></code> 52 script's arguments when building the <code class="program"><a href="/programs/httpd.html">httpd</a></code>.</p> 53 54</div> 55<div id="quickview"><h3 class="directives">Directives</h3> 56<ul id="toc"> 57<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#acceptmutex">AcceptMutex</a></li> 58<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li> 59<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#enableexceptionhook">EnableExceptionHook</a></li> 60<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#group">Group</a></li> 61<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#listen">Listen</a></li> 62<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#listenbacklog">ListenBacklog</a></li> 63<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#lockfile">LockFile</a></li> 64<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#maxclients">MaxClients</a></li> 65<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#maxmemfree">MaxMemFree</a></li> 66<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li> 67<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li> 68<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#minsparethreads">MinSpareThreads</a></li> 69<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#pidfile">PidFile</a></li> 70<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li> 71<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li> 72<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#serverlimit">ServerLimit</a></li> 73<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#startservers">StartServers</a></li> 74<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#threadlimit">ThreadLimit</a></li> 75<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#threadsperchild">ThreadsPerChild</a></li> 76<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#threadstacksize">ThreadStackSize</a></li> 77<li><img alt="" src="/images/right.gif" /> <a href="mpm_common.html#user">User</a></li> 78</ul> 79<h3>Topics</h3> 80<ul id="topics"> 81<li><img alt="" src="/images/down.gif" /> <a href="#how-it-works">How it Works</a></li> 82<li><img alt="" src="/images/down.gif" /> <a href="#requirements">Requirements</a></li> 83</ul><h3>See also</h3> 84<ul class="seealso"> 85<li><a href="worker.html">The worker MPM</a></li> 86</ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 87<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 88<div class="section"> 89<h2><a name="how-it-works" id="how-it-works">How it Works</a></h2> 90 <p>This MPM tries to fix the 'keep alive problem' in HTTP. After a client 91 completes the first request, the client can keep the connection 92 open, and send further requests using the same socket. This can 93 save significant overhead in creating TCP connections. However, 94 Apache traditionally keeps an entire child process/thread waiting 95 for data from the client, which brings its own disadvantages. To 96 solve this problem, this MPM uses a dedicated thread to handle both 97 the Listening sockets, and all sockets that are in a Keep Alive 98 state.</p> 99 100 <p>The MPM assumes that the underlying <code>apr_pollset</code> 101 implementation is reasonably threadsafe. This enables the MPM to 102 avoid excessive high level locking, or having to wake up the listener 103 thread in order to send it a keep-alive socket. This is currently 104 only compatible with KQueue and EPoll.</p> 105 106</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 107<div class="section"> 108<h2><a name="requirements" id="requirements">Requirements</a></h2> 109 <p>This MPM depends on <a class="glossarylink" href="/glossary.html#apr" title="see glossary">APR</a>'s atomic 110 compare-and-swap operations for thread synchronization. If you are 111 compiling for an x86 target and you don't need to support 386s, or 112 you are compiling for a SPARC and you don't need to run on 113 pre-UltraSPARC chips, add 114 <code>--enable-nonportable-atomics=yes</code> to the 115 <code class="program"><a href="/programs/configure.html">configure</a></code> script's arguments. This will cause 116 APR to implement atomic operations using efficient opcodes not 117 available in older CPUs.</p> 118 119 <p>This MPM does not perform well on older platforms which lack good 120 threading, but the requirement for EPoll or KQueue makes this 121 moot.</p> 122 123 <ul> 124 125 <li>To use this MPM on FreeBSD, FreeBSD 5.3 or higher is recommended. 126 However, it is possible to run this MPM on FreeBSD 5.2.1, if you 127 use <code>libkse</code> (see <code>man libmap.conf</code>).</li> 128 129 <li>For NetBSD, at least version 2.0 is recommended.</li> 130 131 <li>For Linux, a 2.6 kernel is recommended. It is also necessary to 132 ensure that your version of <code>glibc</code> has been compiled 133 with support for EPoll.</li> 134 135 </ul> 136</div> 137</div> 138<div class="bottomlang"> 139<p><span>Available Languages: </span><a href="/en/mod/event.html" title="English"> en </a></p> 140</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> 141<script type="text/javascript"><!--//--><![CDATA[//><!-- 142var comments_shortname = 'httpd'; 143var comments_identifier = 'http://httpd.apache.org/docs/2.2/mod/event.html'; 144(function(w, d) { 145 if (w.location.hostname.toLowerCase() == "httpd.apache.org") { 146 d.write('<div id="comments_thread"><\/div>'); 147 var s = d.createElement('script'); 148 s.type = 'text/javascript'; 149 s.async = true; 150 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; 151 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); 152 } 153 else { 154 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); 155 } 156})(window, document); 157//--><!]]></script></div><div id="footer"> 158<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> 159<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[//><!-- 160if (typeof(prettyPrint) !== 'undefined') { 161 prettyPrint(); 162} 163//--><!]]></script> 164</body></html>
