| From | Sent On | Attachments |
|---|---|---|
| Jeff Trawick | Oct 8, 2012 7:31 am | |
| Rich Bowen | Oct 8, 2012 8:25 am | |
| Rich Bowen | Oct 8, 2012 4:37 pm |
| Subject: | Fwd: svn commit: r1395417 - in /httpd/httpd/trunk/docs/manual: mpm.html.en mpm.xml | |
|---|---|---|
| From: | Jeff Trawick (traw...@gmail.com) | |
| Date: | Oct 8, 2012 7:31:57 am | |
| List: | org.apache.httpd.docs | |
---------- Forwarded message ---------- From: Jeff Trawick <traw...@gmail.com> Date: Mon, Oct 8, 2012 at 8:34 AM Subject: Re: svn commit: r1395417 - in /httpd/httpd/trunk/docs/manual: mpm.html.en mpm.xml To: de...@httpd.apache.org
On Sun, Oct 7, 2012 at 6:59 PM, <rbo...@apache.org> wrote:
Author: rbowen Date: Sun Oct 7 22:59:14 2012 New Revision: 1395417
URL: http://svn.apache.org/viewvc?rev=1395417&view=rev Log: Adds some clarification to the statement that the default MPM is selected based on platform capabilities.
Modified: httpd/httpd/trunk/docs/manual/mpm.html.en httpd/httpd/trunk/docs/manual/mpm.xml
Modified: httpd/httpd/trunk/docs/manual/mpm.html.en
URL:
http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mpm.html.en?rev=1395417&r1=1395416&r2=1395417&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/mpm.html.en (original)
+++ httpd/httpd/trunk/docs/manual/mpm.html.en Sun Oct 7 22:59:14 2012
@@ -99,6 +99,28 @@ choice at compile-time.</p>
<code class="module"><a href="./mod/event.html">event</a></code>, depending
on platform capabilities</td></tr>
<tr class="odd"><td>Windows</td><td><code class="module"><a
href="./mod/mpm_winnt.html">mpm_winnt</a></code></td></tr>
</table>
+
+<div class="note"><p>Here, 'Unix' is used to mean Unix-like operating systems,
such as
+Linux, BSD, Solaris, Mac OS X, etc.</p></div>
+
+<p>In the case of Unix, the decision as to which MPM is installed is
+based on two questions:</p>
+<p>1. Does the system support <a
href="http://en.wikipedia.org/wiki/Threads_(computer_science)">threads</a>?</p>
+<p>2. Does the system support <a
href="http://en.wikipedia.org/wiki/Polling_(computer_science)">polling</a>?</p>
+
+<p>If the answer to both questions is 'yes', the default MPM is
+<code class="module"><a href="./mod/event.html">event</a></code>.</p>
It isn't that simple.
APR_POLLSET_THREADSAFE has to be supported, and that is more than the well-known capabilities of threads and polling.
APR_POLLSET_THREADSAFE means that the platform has an advanced polling mechanism which allows pollsets to be manipulated in a certain way, and that APR has an implementation that uses that mechanism.
Linux, Solaris, and FreeBSD/Mac OS X are platforms that satisify both characteristics. z/OS is a platform that has an advanced polling mechanism but without an APR implementation in the stable branches. Neither AIX nor HP-UX have APR implementations, though I'd guess that the OS has the feature and nobody has gotten around to exploiting it in APR.
+
+<p>If The answer to #1 is 'yes', but the answer to #2 is 'no', the
+default will be <code class="module"><a
href="./mod/worker.html">worker</a></code>.</p>
+
+<p>If the answer to both questions is 'no', then the default MPM will be
+<code class="module"><a href="./mod/prefork.html">prefork</a></code>.</p>
+
+<p>In practical terms, this means that the default will almost always be
+<code class="module"><a href="./mod/event.html">event</a></code>, as all modern
operating systems support these
+two features.</p>
+
</div><div class="top"><a href="#page-header"><img alt="top"
src="./images/up.gif" /></a></div>
<div class="section">
<h2><a name="static" id="static">Building an MPM as a static module</a></h2>
Modified: httpd/httpd/trunk/docs/manual/mpm.xml
URL:
http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mpm.xml?rev=1395417&r1=1395416&r2=1395417&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/mpm.xml (original)
+++ httpd/httpd/trunk/docs/manual/mpm.xml Sun Oct 7 22:59:14 2012
@@ -89,6 +89,30 @@ choice at compile-time.</p>
<module>event</module>, depending on platform capabilities</td></tr>
<tr><td>Windows</td><td><module>mpm_winnt</module></td></tr>
</table>
+
+<note><p>Here, 'Unix' is used to mean Unix-like operating systems, such as
+Linux, BSD, Solaris, Mac OS X, etc.</p></note>
+
+<p>In the case of Unix, the decision as to which MPM is installed is
+based on two questions:</p>
+<p>1. Does the system support <a
+href="http://en.wikipedia.org/wiki/Threads_(computer_science)">threads</a>?</p>
+<p>2. Does the system support <a
+href="http://en.wikipedia.org/wiki/Polling_(computer_science)">polling</a>?</p>
+
+<p>If the answer to both questions is 'yes', the default MPM is
+<module>event</module>.</p>
+
+<p>If The answer to #1 is 'yes', but the answer to #2 is 'no', the
+default will be <module>worker</module>.</p>
+
+<p>If the answer to both questions is 'no', then the default MPM will be
+<module>prefork</module>.</p>
+
+<p>In practical terms, this means that the default will almost always be
+<module>event</module>, as all modern operating systems support these
+two features.</p>
+
</section>
<section id="static"><title>Building an MPM as a static module</title>
-- Born in Roswell... married an alien... http://emptyhammock.com/
-- Born in Roswell... married an alien... http://emptyhammock.com/





