PK75174: AUTO-ENABLE COMPRESSED REFS ON AIX PPC64 IF HEAPSIZE LESS THAN 25 GIGABYTES

Fixes are available

APAR status

Closed as program error.

Error description

The JVM option -Xcompressedrefs should automatically be added to
the Launch command of a WebSphere Application Server process
running on the AIX ppc64 architecture when the heapsize is
less than 25 gigabytes and the JVM option -Xnocompressedrefs
is not specified.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  All IBM WebSphere Application Server        *
*                  version 7.0 users on AIX 64 BIT             *
*                  architecture platforms.                     *
****************************************************************
* PROBLEM DESCRIPTION: On the AIX 64 bit platform, the launch  *
*                      server command does not by default      *
*                      launch a server with the JVM option     *
*                      -Xcompressedrefs enabled when the heap  *
*                      size is less than 25 gigabytes.         *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The compressed references option of the IBM implementation of
the 64-bit Java SE Runtime Environment (JRE) Version 6.0
lets you limit all of the memory references to 32-bit size.
Typically, the 64-bit JVMs use more heap space than the 32-bit
JVMs because they use 64-bit wide memory references to address
memory. The heap that is addressable by the 64-bit reference
is orders of magnitude larger than the 32-bit heap, but in the
real world, a heap that requires all 64-bits for addressing is
typically not required. Compressing the references reduces the
size of the addresses and makes more efficient use of the heap.
Compressing these references also improves the processor cache
and bus utilization, thereby improving performance.

If neither the -Xcompressedrefs nor -Xnocompressedrefs option
is specified on the launch command of an AIX 64-bit server
process, and the heap size is less than 25 gigabytes, then the
-Xcompressedrefs option should be added to the launch command.

Problem conclusion

The code has been modified to add the -Xcompressedrefs to the
launch command if neither the -Xcompressedrefs nor
-Xnocompressedrefs option is specified on launch invocation and
the heap size is less than 25 gigabytes.

The fix for this APAR is currently targeted for inclusion in
fixpack 7.0.0.3.  Please refer to the Recommended Updates
page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PK75174
Reported component name
WEBSPHERE APP S
Reported component ID
5724J0800
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2008-11-06
Closed date
2008-11-11
Last modified date
2008-11-11

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
WEBSPHERE APP S
Fixed component ID
5724J0800

Applicable component levels

R700 PSY
UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
23 October 2021

Tips

PK75174: AUTO-ENABLE COMPRESSED REFS ON AIX PPC64 IF HEAPSIZE LESS THAN 25 GIGABYTES

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R700 PSY

Document Information

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