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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 | + | | introduction = Tuning the garbage collection (GC) of the JVM 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 | + | | 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 | + | To print the implicit flags with which the JVM is configured: |
-XX:+PrintCommandLineFlags | -XX:+PrintCommandLineFlags | ||
| Line 9: | Line 9: | ||
-XX:+DisableExplicitGC | -XX:+DisableExplicitGC | ||
| − | + | To print the date and time stamps of GC activity with details: | |
-XX:+PrintGCDateStamps \ | -XX:+PrintGCDateStamps \ | ||
-XX:+PrintGCTimeStamps \ | -XX:+PrintGCTimeStamps \ | ||
| Line 15: | Line 15: | ||
-XX:+PrintTenuringDistribution | -XX:+PrintTenuringDistribution | ||
| − | + | To log GC details to a file: | |
-Xloggc:[path/to/gc.log] | -Xloggc:[path/to/gc.log] | ||
| − | + | 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 | + | To use the concurrent marksweep GC with full GC at 80% old generation full: |
-XX:+UseConcMarkSweepGC \ | -XX:+UseConcMarkSweepGC \ | ||
-XX:CMSInitiatingOccupancyFraction=80, | -XX:CMSInitiatingOccupancyFraction=80, | ||
}} | }} | ||
Revision as of 13:09, 24 February 2011
Introduction
Tuning the garbage collection (GC) of the JVM 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,