mirror of
https://github.com/apache/httpd.git
synced 2025-10-30 08:05:39 +03:00
05dce833d2
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@924467 13f79535-47bb-0310-9956-ffa450edef68
181 lines
13 KiB
XML
181 lines
13 KiB
XML
<?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>worker - 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 2.3</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 2.3</a> > <a href="./">Modules</a></div>
|
||
<div id="page-content">
|
||
<div id="preamble"><h1>Apache MPM worker</h1>
|
||
<div class="toplang">
|
||
<p><span>Available Languages: </span><a href="../de/mod/worker.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
|
||
<a href="../en/mod/worker.html" title="English"> en </a> |
|
||
<a href="../ja/mod/worker.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
|
||
<a href="../tr/mod/worker.html" hreflang="tr" rel="alternate" title="T<>rk<72>e"> tr </a></p>
|
||
</div>
|
||
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Multi-Processing Module implementing a hybrid
|
||
multi-threaded multi-process web server</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<EFBFBD>Identifier:</a></th><td>mpm_worker_module</td></tr>
|
||
<tr><th><a href="module-dict.html#SourceFile">Source<EFBFBD>File:</a></th><td>worker.c</td></tr></table>
|
||
<h3>Summary</h3>
|
||
|
||
<p>This Multi-Processing Module (MPM) implements a hybrid
|
||
multi-process multi-threaded server. By using threads to serve
|
||
requests, it is able to serve a large number of requests with
|
||
fewer system resources than a process-based server. However, it
|
||
retains much of the stability of a process-based server by
|
||
keeping multiple processes available, each with many threads.</p>
|
||
|
||
<p>The most important directives used to control this MPM are
|
||
<code class="directive"><a href="../mod/mpm_common.html#threadsperchild">ThreadsPerChild</a></code>, which
|
||
controls the number of threads deployed by each child process and
|
||
<code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code>, which
|
||
controls the maximum total number of threads that may be
|
||
launched.</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#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="mod_unixd.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#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#receivebuffersize">ReceiveBufferSize</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="mod_unixd.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>
|
||
</ul><h3>See also</h3>
|
||
<ul class="seealso">
|
||
<li><a href="../bind.html">Setting which addresses and ports Apache HTTP Server uses</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>A single control process (the parent) is responsible for launching
|
||
child processes. Each child process creates a fixed number of server
|
||
threads as specified in the <code class="directive"><a href="../mod/mpm_common.html#threadsperchild">ThreadsPerChild</a></code> directive, as well
|
||
as a listener thread which listens for connections and passes them
|
||
to a server thread for processing when they arrive.</p>
|
||
|
||
<p>Apache HTTP Server always tries to maintain a pool of <dfn>spare</dfn> or
|
||
idle server threads, which stand ready to serve incoming
|
||
requests. In this way, clients do not need to wait for a new
|
||
threads or processes to be created before their requests can be
|
||
served. The number of processes that will initially launched is
|
||
set by the <code class="directive"><a href="../mod/mpm_common.html#startservers">StartServers</a></code>
|
||
directive. During operation, the server assesses the total number
|
||
of idle threads in all processes, and forks or kills processes to
|
||
keep this number within the boundaries specified by <code class="directive"><a href="../mod/mpm_common.html#minsparethreads">MinSpareThreads</a></code> and <code class="directive"><a href="../mod/mpm_common.html#maxsparethreads">MaxSpareThreads</a></code>. Since this
|
||
process is very self-regulating, it is rarely necessary to modify
|
||
these directives from their default values. The maximum number of
|
||
clients that may be served simultaneously (i.e., the maximum total
|
||
number of threads in all processes) is determined by the
|
||
<code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code> directive.
|
||
The maximum number of active child processes is determined by
|
||
the <code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code>
|
||
directive divided by the <code class="directive"><a href="../mod/mpm_common.html# threadsperchild">
|
||
ThreadsPerChild</a></code> directive.</p>
|
||
|
||
<p>Two directives set hard limits on the number of active child
|
||
processes and the number of server threads in a child process,
|
||
and can only be changed by fully stopping the server and then
|
||
starting it again. <code class="directive"><a href="../mod/mpm_common.html#serverlimit ">ServerLimit
|
||
</a></code> is a hard limit on the number of active child
|
||
processes, and must be greater than or equal to the
|
||
<code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code>
|
||
directive divided by the <code class="directive"><a href="../mod/mpm_common.html# threadsperchild">
|
||
ThreadsPerChild</a></code> directive.
|
||
<code class="directive"><a href="../mod/mpm_common.html#threadlimit">ThreadLimit</a></code> is a hard
|
||
limit of the number of server threads, and must be greater than
|
||
or equal to the <code class="directive"><a href="../mod/mpm_common.html#threadsperchild">ThreadsPerChild</a></code> directive.</p>
|
||
|
||
<p>In addition to the set of active child processes, there may
|
||
be additional child processes which are terminating, but where at
|
||
least one server thread is still handling an existing client
|
||
connection. Up to <code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code> terminating processes
|
||
may be present, though the actual number can be expected to be
|
||
much smaller. This behavior can be avoided by disabling the
|
||
termination of individual child processes, which is achieved using
|
||
the following:</p>
|
||
|
||
<ul>
|
||
<li>set the value of <code class="directive"><a href="../mod/mpm_common.html# maxrequestsperchild">
|
||
MaxRequestsPerChild</a></code> to zero</li>
|
||
|
||
<li>set the value of <code class="directive"><a href="../mod/mpm_common.html# maxsparethreads">
|
||
MaxSpareThreads</a></code> to the same value as
|
||
<code class="directive"><a href="../mod/mpm_common.html#maxclients">MaxClients</a></code></li>
|
||
</ul>
|
||
|
||
<p>A typical configuration of the process-thread controls in
|
||
the <code class="module"><a href="../mod/worker.html">worker</a></code> MPM could look as follows:</p>
|
||
|
||
<div class="example"><p><code>
|
||
ServerLimit 16<br />
|
||
StartServers 2<br />
|
||
MaxClients 150<br />
|
||
MinSpareThreads 25<br />
|
||
MaxSpareThreads 75<br />
|
||
ThreadsPerChild 25
|
||
</code></p></div>
|
||
|
||
<p>While the parent process is usually started as <code>root</code>
|
||
under Unix in order to bind to port 80, the child processes and threads
|
||
are launched by the server as a less-privileged user. The <code class="directive"><a href="../mod/mod_unixd.html#user">User</a></code> and <code class="directive"><a href="../mod/mod_unixd.html#group">Group</a></code> directives are used to set
|
||
the privileges of the Apache HTTP Server child processes. The child processes
|
||
must be able to read all the content that will be served, but
|
||
should have as few privileges beyond that as possible. In
|
||
addition, unless <code class="program"><a href="../programs/suexec.html">suexec</a></code> is used,
|
||
these directives also set the privileges which will be inherited
|
||
by CGI scripts.</p>
|
||
|
||
<p><code class="directive"><a href="../mod/mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></code>
|
||
controls how frequently the server recycles processes by killing
|
||
old ones and launching new ones.</p>
|
||
|
||
<p>This MPM uses the <code>mpm-accept</code> mutex to serialize
|
||
access to incoming connections when subject to the thundering herd
|
||
problem (generally, when there are multiple listening sockets).
|
||
The implementation aspects of this mutex can be configured with the
|
||
<code class="directive"><a href="../mod/core.html#mutex">Mutex</a></code> directive. The <a href="../misc/perf-tuning.html">performance hints</a>
|
||
documentation has additional information about this mutex.</p>
|
||
</div>
|
||
</div>
|
||
<div class="bottomlang">
|
||
<p><span>Available Languages: </span><a href="../de/mod/worker.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
|
||
<a href="../en/mod/worker.html" title="English"> en </a> |
|
||
<a href="../ja/mod/worker.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
|
||
<a href="../tr/mod/worker.html" hreflang="tr" rel="alternate" title="T<>rk<72>e"> tr </a></p>
|
||
</div><div id="footer">
|
||
<p class="apache">Copyright 2010 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> |