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Thread Contention Performance Issue On WebCenter Sites Cache with JRockit [unlocked] Threads (Doc ID 1644765.1)

Last updated on JANUARY 17, 2018

Applies to:

Oracle WebCenter Sites - Version 7.5.2 and later
Information in this document applies to any platform.

Symptoms

Performance issues occur on delivery environment while under load. Sometimes, the Weblogic thread pool suddenly grows with active threads and we can see many requests locked on some Sites internal locks. Most often, when there are these slow performance periods, the site is still working while the thread pool is growing. This leads to delays in the site's responses to end users. This period of delayed responses can last minutes or even be up to one hour, and after that the number of active threads will return to normal. Occasionally, the site does not return to a normal thread count and becomes unresponsive. At this point the only option is to restart the application server.

Thread dumps show that threads are blocked trying to obtain a lock that is [unlocked].

-- Blocked trying to get lock: java/lang/Integer@0x44e74330[unlocked]
  at jrockit/vm/Threads.waitForUnblockSignal()V(Native Method)
  at jrockit/vm/Locks.fatLockBlockOrSpin(Locks.java:1679)[optimized]
  at jrockit/vm/Locks.lockFat(Locks.java:1780)[optimized]
  at jrockit/vm/Locks.monitorEnterSecondStageHard(Locks.java:1312)[optimized]
  at jrockit/vm/Locks.monitorEnterSecondStage(Locks.java:1259)[optimized]
  at COM/FutureTense/Platform/NONE/I.A(y:1749)[inlined]
  at COM/FutureTense/Platform/NONE/F.A(y:433)[optimized]
  at COM/FutureTense/Platform/NONE/B.A(y:84)[optimized]
  at COM/FutureTense/Common/K.syncKillHash(y:593)[inlined]
  [...]

Cause

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