IV65165: TAIL PADDING REQUESTED BY -XAGGRESSIVE PREVENTS HEAP ALLOCATION BELOW BAR

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  Requested Java VM run with command line options -Xaggressive
  -Xlp:objectheap:pagesize=1G -Xcompressedrefs -Xms3G -Xmx3G can
  not allocate object heap below 4G mark (0-shift) for maximum
  performance
  

Local fix

• This issue can be worked around by omit -Xaggressive option
  

Problem summary

• For case if -Xaggressive is requested an object heap would be
  allocated with one extra full page for tail padding. So real
  memory size required for object heap requested in 1G Large Pages
  in this case is 4G (3G for heap plus one extra 1G memory page)
  and this memory can not be allocated below 4G mark to get
  optimum 0-shift for maximum performance
  

Problem conclusion

• For case -Xaggressive -Xcompressedrefs apply object heap tail
  padding in case if requested memory page size is smaller then 1G
  only.
  .
  This APAR will be fixed in the following Java Releases:
     7 R1 SR2       (7.1.2.0)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, Java maintenance is available
  from:
             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

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