From: Luca Toscano <elukey@apache.org>
Date: Sun, 14 Feb 2016 08:52:23 +0000 (+0000)
Subject: Documentation rebuild.
X-Git-Tag: 2.5.0-alpha~2077
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=12b3bfe1a75d774d1501711233c76aaa4750840f;p=apache

Documentation rebuild.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1730299 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/docs/manual/expr.html.en b/docs/manual/expr.html.en
index a85dbc934d..1d679fabbc 100644
--- a/docs/manual/expr.html.en
+++ b/docs/manual/expr.html.en
@@ -23,8 +23,7 @@
 <div id="path">
 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="./">Version 2.5</a></div><div id="page-content"><div id="preamble"><h1>Expressions in Apache HTTP Server</h1>
 <div class="toplang">
-<p><span>Available Languages: </span><a href="./edited/expr.html" hreflang="edited" rel="alternate" title="">&nbsp;edited&nbsp;</a> |
-<a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
+<p><span>Available Languages: </span><a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
 <a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
 </div>
 
@@ -623,8 +622,7 @@ Header always set CustomHeader my-value "expr=%{REQUEST_URI} =~ m#^/special_path
     are available for versions 2.5.0 and later.</p>
 </div></div>
 <div class="bottomlang">
-<p><span>Available Languages: </span><a href="./edited/expr.html" hreflang="edited" rel="alternate" title="">&nbsp;edited&nbsp;</a> |
-<a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
+<p><span>Available Languages: </span><a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
 <a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
 </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&amp;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>
 <script type="text/javascript"><!--//--><![CDATA[//><!--
diff --git a/docs/manual/mod/event.html.en b/docs/manual/mod/event.html.en
index edc3c571d7..ed5778247c 100644
--- a/docs/manual/mod/event.html.en
+++ b/docs/manual/mod/event.html.en
@@ -154,7 +154,7 @@ of the <code class="directive">AsyncRequestWorkerFactor</code>.</p>
         thread serving the response content can flush the first bytes until <code>EWOULDBLOCK</code>
         or <code>EAGAIN</code> is returned, delegating the rest to the listener. This one in turn
         waits for an event on the socket, and delegates the work to flush the rest of the content
-        to the first idle worker thread. Meanwhile in the latter example (FCGI/CGI/proxed content)
+        to the first idle worker thread. Meanwhile in the latter example (FCGI/CGI/proxied content)
         the MPM can't predict the end of the response and a worker thread has to finish its work
         before returning the control to the listener. The only alternative is to buffer the 
         response in memory, but it wouldn't be the safest option for the sake of the
@@ -231,12 +231,15 @@ of the <code class="directive">AsyncRequestWorkerFactor</code>.</p>
     no worker thread is available to handle new work on established async
     connections.</p>
 
-    <p>To mitigate this problem, the event MPM does two things: Firstly, it
-    limits the number of connections accepted per process, depending on the
-    number of idle request workers. Secondly, if all workers are busy, it will
-    close connections in keep-alive state even if the keep-alive timeout has
-    not expired. This allows the respective clients to reconnect to a
-    different process which may still have worker threads available.</p>
+    <p>To mitigate this problem, the event MPM does two things:</p>
+    <ul>
+        <li>it limits the number of connections accepted per process, depending on the
+            number of idle request workers;</li>
+        <li>if all workers are busy, it will
+            close connections in keep-alive state even if the keep-alive timeout has
+            not expired. This allows the respective clients to reconnect to a
+            different process which may still have worker threads available.</li>
+    </ul>
 
     <p>This directive can be used to fine-tune the per-process connection
     limit. A process will only accept new connections if the current number of
@@ -249,13 +252,70 @@ of the <code class="directive">AsyncRequestWorkerFactor</code>.</p>
         <var>number of idle workers</var>)
     </strong></p>
 
-    <p>This means the absolute maximum numbers of concurrent connections is:</p>
+    <div class="note"><h3>Idle connections handled by each process</h3>
+    <pre class="prettyprint lang-config">max_connections = ThreadsPerChild + (AsyncRequestWorkerFactor * idle_workers)
+
+ThreadsPerChild = idle_workers + busy_workers
+            
+max_connections = (idle_workers + busy_workers) + (AsyncRequestWorkerFactor * idle_workers)
+                = busy_workers + (AsyncRequestWorkerFactor + 1) * idle_workers 
+
+max_connections = max_idle_connections + busy_workers 
+
+max_idle_connections + busy_workers = 
+                busy_workers + (AsyncRequestWorkerFactor + 1) * idle_workers 
+
+max_idle_connections = (AsyncRequestWorkerFactor + 1) * idle_workers</pre>
+
+    </div>
+
+    <p>The absolute maximum numbers of concurrent connections is:</p>
 
     <p class="indent"><strong>
         (<code class="directive">AsyncRequestWorkerFactor</code> + 1) *
         <code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code>
     </strong></p>
 
+
+    <div class="note"><h3>Example 1</h3>
+    <pre class="prettyprint lang-config">ThreadsPerChild = 10 
+ServerLimit = 4
+MaxRequestWorkers = 40
+AsyncRequestWorkerFactor = 2</pre>
+
+
+    <p>If all the processes have all threads idle then: </p>
+
+    <pre class="prettyprint lang-config">idle_workers = 10</pre>
+
+
+    <p>We can calculate the absolute maximum numbers of concurrent connections in two ways:</p>
+    
+    <pre class="prettyprint lang-config">max_connections = (ThreadsPerChild + (AsyncRequestWorkerFactor * idle_workers)) * ServerLimit 
+                = (10 + (2 * 10)) * 4 = 120
+    
+max_connections = (AsyncRequestWorkerFactor + 1) * MaxRequestWorkers 
+                = (2 + 1) * 40 = 120</pre>
+
+    </div>
+
+    <p>The above example is only related to a theoretical maximum, let's take a look to a more common use case:</p>
+
+    <div class="note"><h3>Example 2</h3>
+    <pre class="prettyprint lang-config">ThreadsPerChild = 10
+ServerLimit = 4
+AsyncRequestWorkerFactor = 2
+MaxRequestWorkers = 40
+
+idle_workers = 4 (average for all the processes to keep it simple)
+
+max_connections = (ThreadsPerChild + (AsyncRequestWorkerFactor * idle_workers)) * ServerLimit 
+                = (10 + (2 * 4)) * 4 = 72</pre>
+
+    </div>
+
+    <p>Tuning <code class="directive">AsyncRequestWorkerFactor</code> requires knowledge about the traffic handled by httpd in each specific use case, so changing the default value requires extensive testing and data gathering from <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>.</p>
+
     <p><code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code> was called
     <code class="directive">MaxClients</code> prior to version 2.3.13. The above value
     shows that the old name did not accurately describe its meaning for the event MPM.</p>
diff --git a/docs/manual/mod/event.xml.fr b/docs/manual/mod/event.xml.fr
index 91209abce7..71bf8f56cd 100644
--- a/docs/manual/mod/event.xml.fr
+++ b/docs/manual/mod/event.xml.fr
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
 <?xml-stylesheet type="text/xsl" href="../style/manual.fr.xsl"?>
-<!-- English Revision: 1514214:1729945 (outdated) -->
+<!-- English Revision: 1514214:1730297 (outdated) -->
 <!-- French translation : Lucien GENTIS -->
 <!-- Reviewed by : Vincent Deffontaines -->