<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX This file is generated from xml source: DO NOT EDIT XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX --> <title>event - Apache HTTP Server</title> <link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> <link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> <link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> <link href="../images/favicon.ico" rel="shortcut icon" /></head> <body> <div id="page-header"> <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> <p class="apache">Apache HTTP Server Version 2.2</p> <img alt="" src="../images/feather.gif" /></div> <div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> <div id="path"> <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> <div id="page-content"> <div id="preamble"><h1>Apache MPM event</h1> <div class="toplang"> <p><span>Available Languages: </span><a href="../en/mod/event.html" title="English"> en </a></p> </div> <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> MPM</td></tr> <tr><th><a href="module-dict.html#Status">Status:</a></th><td>MPM</td></tr> <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>mpm_event_module</td></tr> <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>event.c</td></tr></table> <h3>Summary</h3> <div class="warning"><h3>Warning</h3> <p>This MPM is experimental, so it may or may not work as expected.</p> </div> <p>The <code class="module"><a href="../mod/event.html">event</a></code> Multi-Processing Module (MPM) is designed to allow more requests to be served simultaneously by passing off some processing work to supporting threads, freeing up the main threads to work on new requests. It is based on the <code class="module"><a href="../mod/worker.html">worker</a></code> MPM, which implements a hybrid multi-process multi-threaded server. Run-time configuration directives are identical to those provided by <code class="module"><a href="../mod/worker.html">worker</a></code>.</p> <p>To use the <code class="module"><a href="../mod/event.html">event</a></code> MPM, add <code>--with-mpm=event</code> to the <code class="program"><a href="../programs/configure.html">configure</a></code> script's arguments when building the <code class="program"><a href="../programs/httpd.html">httpd</a></code>.</p> </div> <div id="quickview"><h3 class="directives">Directives</h3> <ul id="toc"> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#acceptmutex">AcceptMutex</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#enableexceptionhook">EnableExceptionHook</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#group">Group</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#listen">Listen</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#listenbacklog">ListenBacklog</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#lockfile">LockFile</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxclients">MaxClients</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxmemfree">MaxMemFree</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#minsparethreads">MinSpareThreads</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#pidfile">PidFile</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#serverlimit">ServerLimit</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#startservers">StartServers</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#threadlimit">ThreadLimit</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#threadsperchild">ThreadsPerChild</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#threadstacksize">ThreadStackSize</a></li> <li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#user">User</a></li> </ul> <h3>Topics</h3> <ul id="topics"> <li><img alt="" src="../images/down.gif" /> <a href="#how-it-works">How it Works</a></li> <li><img alt="" src="../images/down.gif" /> <a href="#requirements">Requirements</a></li> </ul><h3>See also</h3> <ul class="seealso"> <li><a href="worker.html">The worker MPM</a></li> </ul></div> <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> <div class="section"> <h2><a name="how-it-works" id="how-it-works">How it Works</a></h2> <p>This MPM tries to fix the 'keep alive problem' in HTTP. After a client completes the first request, the client can keep the connection open, and send further requests using the same socket. This can save signifigant overhead in creating TCP connections. However, Apache traditionally keeps an entire child process/thread waiting for data from the client, which brings its own disadvantages. To solve this problem, this MPM uses a dedicated thread to handle both the Listening sockets, and all sockets that are in a Keep Alive state.</p> <p>The MPM assumes that the underlying <code>apr_pollset</code> implementation is reasonably threadsafe. This enables the MPM to avoid excessive high level locking, or having to wake up the listener thread in order to send it a keep-alive socket. This is currently only compatible with KQueue and EPoll.</p> </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> <div class="section"> <h2><a name="requirements" id="requirements">Requirements</a></h2> <p>This MPM depends on <a class="glossarylink" href="../glossary.html#apr" title="see glossary">APR</a>'s atomic compare-and-swap operations for thread synchronization. If you are compiling for an x86 target and you don't need to support 386s, or you are compiling for a SPARC and you don't need to run on pre-UltraSPARC chips, add <code>--enable-nonportable-atomics=yes</code> to the <code class="program"><a href="../programs/configure.html">configure</a></code> script's arguments. This will cause APR to implement atomic operations using efficient opcodes not available in older CPUs.</p> <p>This MPM does not perform well on older platforms which lack good threading, but the requirement for EPoll or KQueue makes this moot.</p> <ul> <li>To use this MPM on FreeBSD, FreeBSD 5.3 or higher is recommended. However, it is possible to run this MPM on FreeBSD 5.2.1, if you use <code>libkse</code> (see <code>man libmap.conf</code>).</li> <li>For NetBSD, at least version 2.0 is recommended.</li> <li>For Linux, a 2.6 kernel is recommended. It is also necessary to ensure that your version of <code>glibc</code> has been compiled with support for EPoll.</li> </ul> </div> </div> <div class="bottomlang"> <p><span>Available Languages: </span><a href="../en/mod/event.html" title="English"> en </a></p> </div><div id="footer"> <p class="apache">Copyright 2012 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> <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div> </body></html>