AEM_Tune your JVM For Better Performance

Environment : AEM 6.3
                      JRE 1.8
  • If you are getting out-of-memory errors, either add memory or make that there isn't a memory leak. 
  • If there is a memory leak, use -XX:-HeapDumpOnOutOfMemoryError to get a heap dump and analyze it to find the root cause. 
  • You can use any heap dump analyzers, such as sap memory analyzer, yourkit profiler, or eclipse memory analyzer.
  • Turn on garbage collection logs to understand the behavior of your application's memory usage.
Make sure that you look at the available JVM options from your JVM vendor. For Java sun, it's here: http://java.sun.com/javase/technologies/hotspot/vmoptions.jsp

Eclipse Memory Analyzer-EMAT Tips

AEM_JVM_VM_Behavioral Options

Behavioral Options


Option and Default ValueDescription
-XX:-AllowUserSignalHandlersDo not complain if the application installs signal handlers. (Relevant to Solaris and Linux only.)
-XX:AltStackSize=16384Alternate signal stack size (in Kbytes). (Relevant to Solaris only, removed from 5.0.)
-XX:-DisableExplicitGCBy default calls to System.gc() are enabled (-XX:-DisableExplicitGC). Use -XX:+DisableExplicitGC to disable calls to System.gc(). Note that the JVM still performs garbage collection when necessary.
-XX:+FailOverToOldVerifierFail over to old verifier when the new type checker fails. (Introduced in 6.)
-XX:+HandlePromotionFailureThe youngest generation collection does not require a guarantee of full promotion of all live objects. (Introduced in 1.4.2 update 11) [5.0 and earlier: false.]
-XX:+MaxFDLimitBump the number of file descriptors to max. (Relevant  to Solaris only.)
-XX:PreBlockSpin=10Spin count variable for use with -XX:+UseSpinning. Controls the maximum spin iterations allowed before entering operating system thread synchronization code. (Introduced in 1.4.2.)
-XX:-RelaxAccessControlCheckRelax the access control checks in the verifier. (Introduced in 6.)
-XX:+ScavengeBeforeFullGCDo young generation GC prior to a full GC. (Introduced in 1.4.1.)
-XX:+UseAltSigsUse alternate signals instead of SIGUSR1 and SIGUSR2 for VM internal signals. (Introduced in 1.3.1 update 9, 1.4.1. Relevant to Solaris only.)
-XX:+UseBoundThreadsBind user level threads to kernel threads. (Relevant to Solaris only.)
-XX:-UseConcMarkSweepGCUse concurrent mark-sweep collection for the old generation. (Introduced in 1.4.1)
-XX:+UseGCOverheadLimitUse a policy that limits the proportion of the VM's time that is spent in GC before an OutOfMemory error is thrown. (Introduced in 6.)
-XX:+UseLWPSynchronizationUse LWP-based instead of thread based synchronization. (Introduced in 1.4.0. Relevant to Solaris only.)
-XX:-UseParallelGCUse parallel garbage collection for scavenges. (Introduced in 1.4.1)
-XX:-UseParallelOldGCUse parallel garbage collection for the full collections. Enabling this option automatically sets -XX:+UseParallelGC. (Introduced in 5.0 update 6.)
-XX:-UseSerialGCUse serial garbage collection. (Introduced in 5.0.)
-XX:-UseSpinningEnable naive spinning on Java monitor before entering operating system thread synchronizaton code. (Relevant to 1.4.2 and 5.0 only.) [1.4.2, multi-processor Windows platforms: true]
-XX:+UseTLABUse thread-local object allocation (Introduced in 1.4.0, known as UseTLE prior to that.) [1.4.2 and earlier, x86 or with -client: false]
-XX:+UseSplitVerifierUse the new type checker with StackMapTable attributes. (Introduced in 5.0.)[5.0: false]
-XX:+UseThreadPrioritiesUse native thread priorities.
-XX:+UseVMInterruptibleIOThread interrupt before or with EINTR for I/O operations results in OS_INTRPT. (Introduced in 6. Relevant to Solaris only.)