mirror of
https://github.com/apache/httpd.git
synced 2025-08-15 23:27:39 +00:00
c8ef6fe380
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96466 13f79535-47bb-0310-9956-ffa450edef68
79 lines
7.3 KiB
Plaintext
79 lines
7.3 KiB
Plaintext
<html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><!--
|
|
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
|
|
This file is generated from xml source: DO NOT EDIT
|
|
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
|
|
--><title>worker - Apache HTTP Server</title><link href="../style/manual.css" type="text/css" rel="stylesheet"></head><body><blockquote><div align="center"><img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]"><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Apache Module worker</h1><table cellspacing="1" cellpadding="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td nowrap="nowrap" valign="top"><span class="help">Description:
|
|
</span></td><td>Multi-Processing Module implementing a hybrid
|
|
multi-threaded multi-process web server</td></tr><tr><td nowrap="nowrap"><a href="module-dict.html#Status" class="help">Status:
|
|
</a></td><td>MPM</td></tr><tr><td nowrap="nowrap"><a href="module-dict.html#ModuleIdentifier" class="help">Module Identifier:
|
|
</a></td><td>mpm_worker_module</td></tr></table></td></tr></table><h2>Summary</h2>
|
|
<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
|
|
less system resources than a process-based server. Yet 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
|
|
<a href="../mod/mpm_common.html#threadsperchild" class="directive"><code class="directive">ThreadsPerChild</code></a>, which
|
|
controls the number of threads deployed by each child process and
|
|
<a href="../mod/mpm_common.html#maxclients" class="directive"><code class="directive">MaxClients</code></a>, which
|
|
controls the maximum total number of threads that may be
|
|
launched.</p>
|
|
|
|
<h2>Directives</h2><ul><li><a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li><li><a href="mpm_common.html#group">Group</a></li><li><a href="mpm_common.html#listen">Listen</a></li><li><a href="mpm_common.html#listenbacklog">ListenBacklog</a></li><li><a href="mpm_common.html#lockfile">LockFile</a></li><li><a href="mpm_common.html#maxclients">MaxClients</a></li><li><a href="mpm_common.html#maxrequestsperchild">MaxRequestsPerChild</a></li><li><a href="mpm_common.html#maxsparethreads">MaxSpareThreads</a></li><li><a href="mpm_common.html#minsparethreads">MinSpareThreads</a></li><li><a href="mpm_common.html#pidfile">PidFile</a></li><li><a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li><li><a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li><li><a href="mpm_common.html#serverlimit">ServerLimit</a></li><li><a href="mpm_common.html#startservers">StartServers</a></li><li><a href="mpm_common.html#threadlimit">ThreadLimit</a></li><li><a href="mpm_common.html#threadsperchild">ThreadsPerChild</a></li><li><a href="mpm_common.html#user">User</a></li></ul><p><strong>See also </strong></p><ul><li><a href="../bind.html">Setting which addresses and
|
|
ports Apache uses</a></li></ul><h2>How it Works</h2>
|
|
<p>Each process has a fixed
|
|
number of threads. The server adjusts to handle load by
|
|
increasing or decreasing the number of processes.</p>
|
|
|
|
<p>A single control process is responsible for launching child
|
|
processes. Each child process creates a fixed number of threads as
|
|
specified in the <a href="../mod/mpm_common.html#threadsperchild" class="directive"><code class="directive">ThreadsPerChild</code></a> directive. The
|
|
individual threads then listen for connections and serve them when
|
|
they arrive.</p>
|
|
|
|
<p>Apache always tries to maintain a pool of <em>spare</em> 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 <a href="../mod/mpm_common.html#startservers" class="directive"><code class="directive">StartServers</code></a>
|
|
directive. Then during operation, Apache assesses the total number
|
|
of idle threads in all processes, and forks or kills processes to
|
|
keep this number within the boundaries specified by <a href="../mod/mpm_common.html#minsparethreads" class="directive"><code class="directive">MinSpareThreads</code></a> and <a href="../mod/mpm_common.html#maxsparethreads" class="directive"><code class="directive">MaxSpareThreads</code></a>. 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
|
|
<a href="../mod/mpm_common.html#maxclients" class="directive"><code class="directive">MaxClients</code></a> directive,
|
|
while the maximum number of processes that can be launched is set
|
|
by the <a href="../mod/mpm_common.html#serverlimit" class="directive"><code class="directive">ServerLimit</code></a>
|
|
directive. <a href="../mod/mpm_common.html#serverlimit" class="directive"><code class="directive">ServerLimit</code></a>
|
|
multiplied by <a href="../mod/mpm_common.html#threadsperchild" class="directive"><code class="directive">ThreadsPerChild</code></a> must be greater
|
|
than or equal to <a href="../mod/mpm_common.html#maxclients" class="directive"><code class="directive">MaxClients</code></a></p>
|
|
|
|
<p>A typical configuration of the process-thread controls in
|
|
the <code><a href="../mod/worker.html">worker</a></code> MPM could look as follows:</p>
|
|
|
|
<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><pre>StartServers 2
|
|
MaxClients 150
|
|
MinSpareThreads 25
|
|
MaxSpareThreads 75
|
|
ThreadsPerChild 25
|
|
ServerLimit 16</pre></code></td></tr></table></blockquote>
|
|
|
|
<p>While the parent process is usually started as root under Unix
|
|
in order to bind to port 80, the child processes and threads are
|
|
launched by Apache as a less-privileged user. The <a href="../mod/mpm_common.html#user" class="directive"><code class="directive">User</code></a> and <a href="../mod/mpm_common.html#group" class="directive"><code class="directive">Group</code></a> directives are used to set
|
|
the privileges of the Apache 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 <a href="../suexec.html">suexec</a> is used,
|
|
these directives also set the privileges which will be inherited
|
|
by CGI scripts.</p>
|
|
|
|
<p><a href="../mod/mpm_common.html#maxrequestsperchild" class="directive"><code class="directive">MaxRequestsPerChild</code></a>
|
|
controls how frequently the server recycles processes by killing
|
|
old ones and launching new ones.</p>
|
|
<hr></blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="../images/index.gif" alt="Index"></a><a href="../"><img src="../images/home.gif" alt="Home"></a></body></html> |