PK68826: ORB TRACING OPTIMIZATION

APAR status

• Closed as program error.

Error description

• Error Message: High CPU utilization in certain ORB
  method(notably
  com/ibm/rmi/io/ObjectStreamClass.isAbstractInterface()), even
  when orb tracing was disabled.
  
  
  Stack Trace: javacore thread stack showing contention:
  "WebContainer : 0" (TID:0x000000012443C300,
  sys_thread_t:0x000000011ED89A90, state:B, native
  ID:0x00000000000E216D) prio=5
  at
  com/ibm/rmi/util/RepositoryId.checkClassCache(RepositoryId.java:
  658(Compiled Code))
  at
  com/ibm/rmi/util/RepositoryId.getClassFromType(RepositoryId.java
  :617(Compiled Code))
  at
  com/ibm/rmi/iiop/CDRInputStream.fast_read_value(CDRInputStream.j
  ava:1990(Compiled Code))
  <deleted for readability>
  
  at
  java/io/ObjectInputStream.readObject(ObjectInputStream.java:357(
  Compiled Code))
  at java/util/TreeMap.buildFromSorted(TreeMap.java:1623(Compiled
  Code))
  at java/util/TreeMap.buildFromSorted(TreeMap.java:1563(Compiled
  Code))
  at java/util/TreeMap.readObject(TreeMap.java(Compiled Code))
  
  at sun/reflect/GeneratedMethodAccessor120.invoke(Bytecode
  PC:40(Compiled Code))
  at
  sun/reflect/DelegatingMethodAccessorImpl.invoke(DelegatingMethod
  AccessorImpl.java:43(Compiled Code))
  at java/lang/reflect/Method.invoke(Method.java:603(Compiled
  Code))
  at
  com/ibm/rmi/io/IIOPInputStream.invokeObjectReader(IIOPInputStrea
  m.java:1689(Compiled Code))
  <deleted for readability>
  
  at
  com/ibm/rmi/io/IIOPInputStream.simpleReadObjectLoop(IIOPInputStr
  eam.java:480(Compiled Code))
  at
  com/ibm/rmi/io/IIOPInputStream.simpleReadObject(IIOPInputStream.
  java:434(Compiled Code))
  at
  com/ibm/rmi/io/ValueHandlerImpl.readValue(ValueHandlerImpl.java:
  201(Compiled Code))
  at
  com/ibm/rmi/iiop/CDRInputStream.read_value(CDRInputStream.java:1
  583(Compiled Code))
  at
  com/ibm/rmi/util/ProxyUtil.copyObject(ProxyUtil.java:451(Compile
  d Code))
  at
  com/ibm/rmi/util/ProxyUtil.invokeWithClassLoaders(ProxyUtil.java
  :755(Compiled Code))
  at
  com/ibm/CORBA/iiop/ClientDelegate.invoke(ClientDelegate.java:115
  5(Compiled Code))
  at
  com/a/b/c/d/_EJB1_Stub.ejbMethod(_EJB1_Stub.java:332(Compiled
  Code))
  ...
  .
  

Local fix

• If the customer scenario reveals slow response times for
  _collocated_ EJB methods (inside WAS), then setting the
  classloader policy to single in conjunction with setting
  pass_by_reference to true will work around the issue.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM WebSphere Application Server Version    *
  *                  6.1 users                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: ORB performance degredation             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The slow processing of requests was caused by the prevalent
  cache design .
  

Problem conclusion

• This defect will be fixed in:
  5.0.0 SR8   (IZ22312)
  Tentatively 5.0.0 SR9   (IZ27662)
  .
  The cache design was overhauled to allow for more concurrent
  access as also the classloading-order which was refactored to
  prevent possible repetition of searches.
  .
  To obtain the fix:
  Install build 20080702 or later (IZ22312)
  Install 5.0.0 SR9 (IZ27662)
  .
  This APAR ships an interim fix for IBM Software Developer's
  Kit APAR IZ22312 and IZ27662. The error description in this
  APAR is from IZ22312 and IZ27662.            .
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IZ22312

• APAR is sysrouted TO one or more of the following:

  PK74459

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R61A PSY

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