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Difference between revisions of "Jetty/Howto/Garbage Collection"

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{{Jetty Howto
 
{{Jetty Howto
| introduction = Tuning the garbage collection of the JVM can greatly improve performance of Jetty.  Specifically it can avoid pauses while the system performs full garbage collections.  Tuning the GC really depends on the behaviour of the application and needs detailed analysis, however there are general recommendations
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| introduction =  
| examples =  
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These options are general to the Sun JVM, and will work in a JDK 6 installation.
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{{Jetty Redirect|http://www.eclipse.org/jetty/documentation/current/garbage-collection.html}}
  
To print the implicit flags that the JVM is configured with:
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Tuning the JVM garbage collection (GC) can greatly improve Jetty performance.  Specifically, you can avoid pauses while the system performs full garbage collections. Optimal tuning of the GC depends on the behaviour of the application and requires detailed analysis, however there are general recommendations.
 +
| examples = These options are general to the Sun JVM, and work in a JDK 6 installation. They provide good information about how your JVM is running; based on that initial information, you can then tune more finely.
 +
 
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To print the implicit flags with which the JVM is configured:
 
     -XX:+PrintCommandLineFlags  
 
     -XX:+PrintCommandLineFlags  
  
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     -XX:+DisableExplicitGC  
 
     -XX:+DisableExplicitGC  
  
to print the date and time stamps of GC activity with details:
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To print the date and time stamps of GC activity with details:
 
     -XX:+PrintGCDateStamps \
 
     -XX:+PrintGCDateStamps \
 
     -XX:+PrintGCTimeStamps \
 
     -XX:+PrintGCTimeStamps \
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     -XX:+PrintTenuringDistribution
 
     -XX:+PrintTenuringDistribution
  
to log GC details to a file:
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To log GC details to a file:
 
     -Xloggc:[path/to/gc.log]  
 
     -Xloggc:[path/to/gc.log]  
  
or to print GC activity with less detail:
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To print GC activity with less detail:
 
     -verbose:gc  
 
     -verbose:gc  
  
To use the concurrent marksweep GC with full GC at 80% old generation full
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To use the concurrent marksweep GC with full GC at 80% old generation full:
 
     -XX:+UseConcMarkSweepGC \
 
     -XX:+UseConcMarkSweepGC \
     -XX:CMSInitiatingOccupancyFraction=80,
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     -XX:CMSInitiatingOccupancyFraction=80
  
 
}}
 
}}

Latest revision as of 13:53, 23 April 2013



Introduction


Tuning the JVM garbage collection (GC) can greatly improve Jetty performance. Specifically, you can avoid pauses while the system performs full garbage collections. Optimal tuning of the GC depends on the behaviour of the application and requires detailed analysis, however there are general recommendations.




Examples

These options are general to the Sun JVM, and work in a JDK 6 installation. They provide good information about how your JVM is running; based on that initial information, you can then tune more finely.

To print the implicit flags with which the JVM is configured:

   -XX:+PrintCommandLineFlags 

To disable explicit GC performed regularly by RMI:

   -XX:+DisableExplicitGC 

To print the date and time stamps of GC activity with details:

   -XX:+PrintGCDateStamps \
   -XX:+PrintGCTimeStamps \
   -XX:+PrintGCDetails \
   -XX:+PrintTenuringDistribution

To log GC details to a file:

   -Xloggc:[path/to/gc.log] 

To print GC activity with less detail:

   -verbose:gc 

To use the concurrent marksweep GC with full GC at 80% old generation full:

   -XX:+UseConcMarkSweepGC \
   -XX:CMSInitiatingOccupancyFraction=80