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   <title>Chapter&nbsp;20.&nbsp;Optimizing Jetty</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="jetty-admin-guide.html" title="Part&nbsp;III.&nbsp;Jetty Administration Guide"><link rel="prev" href="runner.html" title="Chapter&nbsp;19.&nbsp;Jetty Runner"><link rel="next" href="high-load.html" title="High Load"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script>
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            Version: 9.4.28-SNAPSHOT</span></td><td style="width: 50%"></td></tr></table><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter&nbsp;20.&nbsp;Optimizing Jetty</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="runner.html"><i class="fa fa-chevron-left" aria-hidden="true"></i> Previous</a>&nbsp;</td><th width="60%" align="center">Part&nbsp;III.&nbsp;Jetty Administration Guide<br><a accesskey="p" href="index.html"><i class="fa fa-home" aria-hidden="true"></i> Home</a></th><td width="20%" align="right">&nbsp;<a accesskey="n" href="high-load.html">Next <i class="fa fa-chevron-right" aria-hidden="true"></i></a></td></tr></table><hr></div><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="jetty-callout"><h5 class="callout"><a href="http://www.webtide.com/">Contact the core Jetty developers at
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      </p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a name="optimizing"></a>Chapter&nbsp;20.&nbsp;Optimizing Jetty</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="optimizing.html#garbage-collection">Garbage Collection</a></span></dt><dt><span class="section"><a href="high-load.html">High Load</a></span></dt><dt><span class="section"><a href="limit-load.html">Limiting Load</a></span></dt></dl></div><p>There are many ways to optimize Jetty which vary depending on the situation.
Are you trying to optimize for number of requests within a given amount of time?
Are you trying to optimize the serving of static content?
Do you have a large bit of hardware that you want to give entirely over to Jetty to use to its heart&#8217;s delight?
This chapter examines a few of the many different ways to optimize Jetty.</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="garbage-collection"></a>Garbage Collection</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="optimizing.html#garbage-collection-logging-configuration">Garbage Collection Logging Configuration</a></span></dt></dl></div><p>Tuning the JVM garbage collection (GC) can greatly improve the performance of the JVM where Jetty and your application are running.
Optimal tuning of the GC depends on the behavior of the application(s) and requires detailed analysis, but there are general recommendations to follow to at least obtain comprehensive GC logs that can be later analyzed.</p><p>See official <a class="link" href="https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/" target="_top">Java 8</a> and <a class="link" href="https://docs.oracle.com/javase/9/gctuning/introduction-garbage-collection-tuning.htm" target="_top">Java 9</a> Garbage Collection documentation for further assistance.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="garbage-collection-logging-configuration"></a>Garbage Collection Logging Configuration</h3></div></div></div><p>These options are general to OpenJDK (and therefore also for the Oracle JVM).
They provide good information about the GC activity of your JVM, producing logs that can later be analyzed to perform finer tuning.</p><p><b>JDK 8 Garbage Collection Logging Configuration.&nbsp;</b>
</p><div class="screenexample"><pre class="screen">-Xloggc:/path/to/myjettybase/logs/gc.log
-XX:+PrintGCDateStamps
-XX:+PrintGCDetails
-XX:+ParallelRefProcEnabled
-XX:+PrintReferenceGC
-XX:+PrintTenuringDistribution
-XX:+PrintAdaptiveSizePolicy</pre></div><p>
</p><p><b>JDK 9 Garbage Collection Logging Configuration.&nbsp;</b>
</p><div class="screenexample"><pre class="screen">Xlog:gc*,ergo*=trace,ref*=debug,age*=trace:file=/path/to/myjettybase/logs/gc.log:time,level,tags</pre></div><p>
</p><p>There are not many recommended options for GC that can apply to all users.
However, the most obvious one is to disable explicit GC (this is performed regularly by RMI and can introduce an abnormal amount of GC pauses).</p><div class="screenexample"><pre class="screen">-XX:+DisableExplicitGC</pre></div></div></div></div><script type="text/javascript">
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