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I customized my eclipse.ini as suggested in the post What are the best JVM settings for Eclipse? . When I run eclipse with this eclipse.ini. It works well on my machine . I suggested these file to my colleagues . On of them has got this exception . 

UnRecognized vm option -XX:ConcGCThreads .

Exception occured jdk version - 1.6.0_16 .

I am using jdk 1.6.0_24 . How can i know what are all the jvm options supported from jdk 1.6.0_0? .

Eclipse.ini

 -showsplash
-vmargs
-Xincgc
-Xss500k
-Dosgi.requiredJavaVersion=1.6
-Xms512m
-Xmx1024m
-XX:NewSize=8m
-XX:PermSize=128m
-XX:MaxPermSize=150m
-XX:MaxPermHeapExpansion=10m
-XX:+UseConcMarkSweepGC
-XX:CMSInitiatingOccupancyFraction=70
-XX:+UseCMSInitiatingOccupancyOnly
-XX:+UseParNewGC
-XX:+CMSConcurrentMTEnabled
-XX:ConcGCThreads=2
-XX:ParallelGCThreads=2
-XX:+CMSIncrementalPacing
-XX:CMSIncrementalDutyCycleMin=0
-XX:CMSIncrementalDutyCycle=5
-XX:GCTimeRatio=49
-XX:MaxGCPauseMillis=20
-XX:GCPauseIntervalMillis=1000
-XX:+UseCMSCompactAtFullCollection
-XX:+CMSClassUnloadingEnabled
-XX:+DoEscapeAnalysis
-XX:+UseCompressedOops
-XX:+AggressiveOpts
-XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses
-Xverify:none
Community
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kannanrbk
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3 Answers3

1

There is not much you can do except reading the documentation of the JVM you are using.

Henry
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1

I assume you are using Oracle's JDK implementation. The documentation for garbage collection (http://www.oracle.com/technetwork/java/javase/gc-tuning-6-140523.html) doesn't mention the -XX:ConcGCThread option. To my understanding, the option -XX:ParallelGCThreads=2 is only used for the parallel GC. If you dont't experience excessive pauses due to garbage collection I wouldn't bother changing the vm settings for eclipse. The only settings I ever changed for eclipse is MaxPermSize and the heap size.

Maddin
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It depends on the version of JDK you are using and also the JVM and the falgs it supports. Similar discussion I found here. Hope this helps. :

http://www.eclipse.org/forums/index.php/t/87365/

LPD
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