Tuning ParallelGCThreads / ConcGCThreads in CMS on OpenJDK

Solution Verified - Updated -


  • How are ConcGCThreads and ParallelGCThreads calculated?
  • How to tune ConcGCThreads and ParallelGCThreads in CMS?
  • Monitors and benchmarks indicates an overwork of cpu activity and long Garbage Collection pauses while running multiple JBoss EAP instances. What values should I set for ParallelGCThreads / CMSParallelThreads to solve it?


  • Red Hat Enterprise Linux (RHEL)
    • 7.x
  • OpenJDK/OracleJDK 8
    • 8/7 (CMS is deprecated in JDK 11)
  • Red Hat JBoss Enterprise Application Platform (EAP)
    • 7.x

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