IV76936: POOR PERFORMANCE WHEN RUNNING JDMPVIEW COMMANDS ON LARGE SYSTEM DUMPS

APAR status

• Closed as program error.

Error description

• Error Message: Poor performance when running jdmpview commands
  on large system dumps. For example, running the 'info class',
  'info thread' or 'info lock' commands on an 8Gb system dump may
  take approximately 15 mins.
  .
  Stack Trace: at java/util/HashMap$TreeNode.find
  at java/util/HashMap$TreeNode.find
  at java/util/HashMap$TreeNode.find
  at java/util/HashMap$TreeNode.find
  at java/util/HashMap$TreeNode.find
  at java/util/HashMap$TreeNode.putTreeVal
  at java/util/HashMap.putVal
  at java/util/HashMap.put
  at java/util/HashSet.add
  at com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.processFlatMonitor
  at com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.doState
  at com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.doState
  at com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.walk
  at
  com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.runFlatLockMonitorRegio
  nWalk
  at
  com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.initializeFlatLockedMon
  itors
  at
  com/ibm/j9ddr/vm26/j9/walkers/HeapWalker.getFlatLockedMonitors
  at com/ibm/j9ddr/vm26/j9/walkers/MonitorIterator.<init>
  at
  com/ibm/j9ddr/vm26/view/dtfj/java/j9/DTFJMonitorIterator.<init>
  .
  A Java stack trace taken while the command is running shows that
  excessive time is taken when processing flat locked monitors
  during the heap walk.
  

Local fix

Problem summary

• The problem is caused when jdmpview is processing flat locked
  monitors during the heap walk on a large system dump.
  

Problem conclusion

• The DTFJ/DDR API used by jdmpview has been updated to improve
  performance.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR2       (8.0.2.0)
     7    SR9 FP20  (7.0.9.20)
     6 R1 SR8 FP15  (6.1.8.15)
     7 R1 SR3 FP20  (7.1.3.20)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

Temporary fix

Comments

APAR Information

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

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

Fix information

• Fixed component name

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R270 PSY

     UP

• R260 PSY

     UP